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Physiology Class=Book 


( -* ^ s' •wBY'w. 

F. M. Walters, A. M. 

Instructor in Physiology in State Normal School, 
Warrensburg, Mo. 




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■P y 4895 


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PUBLISHED BY 
STAR PUBLISHING COMPANY, 
WARRENSBURG, MO. 


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Copyright, 1895, 

BY 

F. M. WALTERS. 


INDEX 


PAGE 

Absorption.52—54 

Accommodation... ..120 

Adductors..70 

Air passages.30 

Air vesicles.32 

Alimentary canal.42 

Alcohol.126 

Anatomy defined.l 

Aqueous humor. US 

Arteries. 18 

Articulations.70 -72 

Astigmatism.120 

Atmosphere.36—38 

Auditory cells.... 112 

Auditory canal. lio 

Automatic action.98 

Axis cylinder. 84 

Bathing. . 82 

Bile.50 

Blind spot.118 

Blood.10—14 

Bone cells.66 

Bowels, care of.52 

Brain. DO 

Caffeine.128 

Canaliculi.66 

Capillaries.20 

Carbon dioxid. 38 

Cells. 2—4 

Cerebellum.92 

Cerebro-spinal system.90 

Cerebrum.90 

Choroid coat.116 

Ciliary muscle.li* 

Circulation of blood. 16—20 

Circulatory organs.16—18 

Coagulation of blood. 10 

Cochlea.112 

Coffee. 128 

Conjunctiva.122 

Cornea. 116 

Cranial nerves.92—94 

Crystalline lens.118 

Cuticle. 80 

Deglutition. 50 

Dermis.80 

Dialysis .26 

Diaphragm.32 

Digestion.4 »-52 

Digestive glands.44 

Digestive organs.40 

Digestive processes.4 > 

Dissection of 

Cat. 64 

Heart .16 

Lungs.80 

Dissectional review.64 

Ear.110—114 

Effects of alcohol.126 

Endosteum. .66 

Epidermis.80 

Epithelial cells.32—60 

Epithelial tissue.2 

Eustachian tube.1 0 

Excitant fibres.86 

Excretion.58—60 

Excretory organs.58 

Exercise.78. 124 

Experiments to illustrate 

Accommodation .120 

Blind spot. 118 

Breathing...34 


Composition of bones. 

Digestion. 

Digestion of fats. 

Effects of alcohol. 

Function of skin. 

Heart’s action. 

Insensible perspiration. 

Light. 

Osmosis. 

Properties of blood. 

Properties of carbon dioxid 

Properties of oxygen. 

Purpose of mastication.... 

Keflex action.. 

Separation of haemoglobin. 

Sound... 

Stomach digestion. 

Structure of eye. 

Structure of ear.. 

External ear. 

Extensors. 

Eyeball. 

Fatigue... 

Flexors . .. 

F oc u s i n g po vve r o f th e eye. 

Foods. 

Gastric glands. 

Genera) sensations.. 

Glands.. 

Glycogen.. 

Gray matter.. 

Haemoglobin. 

Hair.. 

Haversian canals.. 

Hearing. 

Heart... 

Histology defined.. 

Hygiene defined . 

Hygiene of 

Bones. 

Circulation . 

Dig« stive organs. 

Ear. 

Eve. 

Muscular system. 

Nervous system. 

Respiratory organ 4 . 

suin. 

Inhibitory fibres. 

Insalivation.. 

Internal ear. . 

Tutereostal muscles. 

Intestinal digestion. 

Intestinal glands. 

Involuntary action. 

Involuntary muscles. 

Iris. 

Joints. 

Kidneys. . 

Labyrinth. 

Lacteal s. 

Large intestine. 

Larynx.. 

fie vers. 

bight.. 

Liver . 

Longsightedness. 

Lungs.... 

Lymph and lvmphatios. 

Lymphatic glands. 

L>mph movements. 

Marrow... 


PAGE 

.66 

.40 

.50 

.126 

.82 

.18 

.60 

114—116 

.26 

.10 

.88 

..86—38 

. 48 

.96 

. 12 

.1 IS 

.50 

. 118 

.112 

... 110 

.76 

.....116 

. 76 

.76 

_118 

...56-58 

. 48 

. ..B4 

.46 

.4s 

.84 

.12 

.80 

.56 

108—114 

.13 

.1 

.1 

.. ..72 

.20 

.. 50—52 

.112 

122 

78 

124—128 
. 84—36 

.82 

.84 

.48 

.112 

.31 

.50 

.46 

.96 

.74 

.. .116 
..70—7‘2 
58 

...112 
.... 54 

.44 

.80. 110 
'0 

.... i 14 
, .. . 46 

.120 

..80, 6 ) 
22-24 
24 
24 

. 08 


























































































































































Ma tication.. 

Matrix. 

Medulla oblongata . 

Medullary sheath. 

Meiuhrana tympani. 

Mental action. 

Middle ear. 

Morphea. 

Mouth. 

Mucous membrane,. 

Muscular stimu.i. 

Muscular system . 

MiigoIp ppIIq .... ....... 

Muscles of alimentary canal 

Nails.. 

Narcotics,. 

Nerves. 

Nerve cell. 

Nerve center. 

Nerve fibre. 

Nervous action. 

Nervous control of 

Blood supply. 

Respiration. 

Digestion. 

Nervous ganglia. 

Nervous impulse. 

Nervous system. 

Nervous tissue. 

Nicotine. 

Nitrogenous foods . 

Observation of 

Blood. 

Bone. 

Circulatory organs. 

Muscles. 

Nails.. 

Skin. 

Tissues. 

Oesophagus.. 

< irgans defined.. 

Osmosis. 

Osseous system. 

< >xyg*m. 

Pancreas . .. .. 

Pancreatic juice. 

Pepsin. 

Perimysium. 

Periosteum. 

Perspiration. 

Pharynx.. .. 

IMnsioloeyd fin‘ j d. 

Plan of maintaining life. 

Plan of placing muscles. ... 

Plan of skeleton. 

P a-m a. . 

Pleura.. 

Primitive sheath. . 

Problem in 

A hsorntion. 

Excretion. 

Hearing. 


PAGE 

.48 

.80 

.92 

.84 

.no 

98 

.110 

.128 

.44 

.42 

.76 

...74—78 

.74 

.42 

.80 

. 126-128 

.84 

.81 

.84 

84 

. ..96-98 

.100 

.100 

.102 

.84 

76, 84, 86 
.. 84,128 

. 84 

.128 

.56 

. 10 

.66 

.16 

.74 

.80 

.80 

.1 

.44 

.6 

.26 

...66—72 

.36 

.46 

.50 

.50 

.74 

.66 

.60 

.44 

. . 

.6 

. .. .76 

.68 

.14 

.32 

.84 


.54 
. 60 

112 


Osmosis. 

lleflex action 
Ventilation.. 

Protoplasm. 

Pupil of eye. 

Red corpuscles. 

Red marrow. 

Reflex action . 

Respiration. 

Respiratory organs.. 

Retina. 

Kods and cones. 

Rotators. 

j-alivary gland*. 

Salts. 

Sclerotic coat . 

Semi-circular canals . 

Sensations .. 

Serum. 

Shortsightedness. 

Sight. 

Skeleton. 

Skin. 

Sleep. 

Small intestine. 

Smell. 

Sound.- 

Spinal cord. 

Spinal nerves. 

Sphincters. 

Stimulants. 

Stomach. 

Stomach digestion. 

Sympathetic system,. 

System defined . 

Taste. 

Tea. 

Teeth. 

Temperature sense — 

Theine. 

'thoracic duct. 

Thorax. 

Tissues. 

Tobacco. . 

'tongue. 

Touch. 

Tympanum. 

U rea. 

Urine.. 

Uriniferous tubes.... 

Veins. 

Vestibule. 

Villi. 

Vitreous humor. 

Vocal cords. 

Voice. 

Voluntary action. 

Voluntary muscles... 

Water.. 

White corpuscles. 

White matter. 

Yellow spot. 


PAGE 

.26 

.98 

. 34 

.4 

.116 

.12 

.68 

.96 

....30—36 

. 30 

.116 

.116 

.76 

.46 

.58 

.116 

.112 

.104-122 

.14 

.120 

..114—122 

.68 

80—82, 60 

.124 

.44 

_ ..106 

...108 

. 92 

. 94 

.78 

.. 126— 28 

.44 

.50 

. 88 

.0 

.106 

.128 

.44 

.106 

.128 

.24 

. .. .32—34 

.1-2 

.128 

.44 

.......104 

.110 

.60 

.60 

.60 

.18 

.112 

.54 

.118 

.110 

.110 

.96 

.74 

. 56 

.12 

.84 

.118 































































































































PREFACE. 

The Physiology Class-Book is the outgrowth of an attempt to com¬ 
bine the “text-book” and “lecture” methods of teaching Physiology, and 
has been prepared for the use of students in the Warrensburg State 
Normal School. Recognizing the pedagogical principal that to tell a 
pupil what he can easily find out for himself deprives him of an opportu¬ 
nity to think, while withholding from him what he cannot find out,wastes 
his time in useless endeavor, the aim has been to state in clear, concise 
English what the pupil must be told about the subject. This information 
is intended to serve as a basis for the recitation , and is to be supplement¬ 
ed by text-book references, lectures, experiments, observations, and il¬ 
lustrative drawings. The blank pages are for the recording of experiments, 
observations, etc , by the pupil, so that the completed book may contain 
his own work as well as the subject matter furnished him. 

Throughout, the subject has been treated from the standpoint of a 
natural science. Enough has been said and written of late upon this view 
of Physiology to make a restatement of argument unnecessary here. Such 
a treatment, however, necessitates a clear statement of the principles un¬ 
derlying the science, and a logical arrangement of the parts, based, if pos¬ 
sible, upon some central underlying truth. The central idea in the science 
Physiology is Nature’s plan of maintaining life. For this one purpose all 
the different parts of the human organism are made, directly or indirectly, 
to serve. The aim has been to arrange the parts of the subject in such 
an order that each successive step in the study will reveal more and more 
of this plan to the pupil. 

Further, in teaching a subject as a science, the appeal must be made to 
the pupil’s reasoning powers rather than his memory, and sufficient ex¬ 
perimental and observational work must be done to furnish clear con¬ 
ceptions—the necessary basis for correct thinking. Physiology work should 
be supplemented by laboratory practice. Where this cannot be arranged 
for, class experiments and observations should be furnished by the teacher. 
The experiments and observations given in this book are intended for class 
purposes. The list is suggestive, rather than exhaustive, and contains 
such as require little or no apparatus. 

Next to observations and experiments, in forming clear conceptions, are 
properly made diagrams and drawings. Of the different kinds, those which 
show fundamental relations and the connection of different organs are of 
most value. They may be drawn upon the blackboard or executed on 
heavy manilla paper with colored pencils. A set of the drawings, to be 
used in connection with this book, is in course of preparation, and will be 
furnished by the publishers. 


The reference blanks are to be filled at the teacher’s suggestion, with 
the page numbers of available books upon the given subjects. For reference 
work by the pupil, the following books are recommended : Martin’s Human 
Body, Intermediate Course; Jenkin’s Advanced Lessons in Physiology; and 
Blaisdell’s Our Bodies. For extended study, the advanced works of Foster, 
Martin, Flint, and Kirke, are recommended. 

The necessity of keeping such a book small enough for class purposes 
accounts for the crowded condition of many of the pages and the omission 
of considerable material found in books of similar nature. Still, it is be¬ 
lieved that the principles underlying the science of Physiology have been 
stated and the method suggested for mastering them. 

Warrensbitrg, Mo., Aug. 80, 1895. 


-: O:- 

Directions for Work. 

(For the Pupil.) 

1. The following printed notes are not intended to take the place of a 
text-book, but are to be used in connection with books. The student is 
recommended to consult as many books as he has at his disposal on the 
various subjects, in addition to looking up the references. 

2. Copy on the blank pages the different drawings used in illustrating 
the subject. The drawing in each case should be placed directly opposite 
that portion of the printed notes which it is intended to illustrate. 

8. When experiments are performed, specimens shown, or dissections 
made in class, the important things done and seen should be noted and 
written in ink on the blank pages. 

4. Notes dictated in class and important facts obtained from books or 
other sources may also be inserted. 

5. In the preparation of lessons, commit nothing to memory, but 
think about and try to understand what you see, hear and read. 

G. Keep a neat and orderly book and do not allow the written work to 

lag. 

7. Never attempt to copy a drawing until you thoroughly understand 
it. Then be sure that it is sufficiently accurate in detail to show what it is 
intended to illustrate. 

8. Where questions are asked in the printed notes it is expected that 
the pupil shall think out the answers. If this is carefully done in each 
case, the work which follows will be made easier. 

9. The pupil is his own teacher. Books, specimens, drawings, and 
the instructor, can only serve him as aids in teaching himself. He will 
therefore be careful that he does not pass over any portion of the subject 
without understanding it. 




General Structure and Function of the Body, 

-:o:- 

Methods of Study. The different ways of studying the human body 
are designated by the terms, Anatomy, Physiology, and Hygiene. 

1. A study of the structure of the different parts is called Anatomy.. 
Anatomy is of two kinds, known as Gross Anatomy and Histology. Gross 
Anatomy is a study of the rough, coarse structure—those parts which can 
be readily seen with the naked eye. Histology is a study of the minute 
structure'—those parts which are too-small to be seen with the naked eye 
and whose study requires the use of a miscroscope. 

2. The study of the function or use of the different parts of the body 
and their relation to each other is termed Physiology. 

3. A study of the ways of taking care of the body and keeping its parts 
in good working order is called Hygiene. The conditions which must be 
observed in doing this are termed the “lawsof health.” 

Sources of Information. Information concerning the body may be 
obtained from many sources. The body itself, books which have been 
written about the body, the bodies of other animals, experiments,models,and 
charts will each contribute something to the subject. The true student 
will not confine his investigations to the printed page, but will seek infor¬ 
mation from all sources. 

The Tissues. The different kinds of material which compose the body 
are called tissues. These are to the body what the wood, stone, plaster, 
and other building materials are to a house. In fact, the tissues have been 
called the building materials of the body. The mt st important tissues are as- 
follows: 

1. Osseous or bony. 2. Muscular, of two varieties, the voluntary and 
involuntary. 3. Two varieties of nervous tissue. 4. Elastic and inelastic 
connective tissue. 5. Cartilagenous. 6. Adipose or fatty. 7. Epithe¬ 
lial. 8. Epidermal. 

Observation.— Select the leg of some small animal as a cat, rabbit, frog, or chicken. 
On the outside observe the epidermal tissue in the form of cuticle and hair,claws,or feathers, 
according to the specimen. With a sharp knife lay open the skin and observe tli it: it is at¬ 
tached to the parts underneath by connective tissue. Next observe the amount and ar- 




z 


ranjromeni of the muscular tissue. With a blunt instrument separate the muscles. ^ * 

a .art the connective tissue sheaths, and find the rough strips of connective tissue Jhe te 
.'ons; which attach them to the hones Find near the central part of the leg some w 
ah .telling cords (nerves) which form one variety of nervous tissue. At the e' d of the bones 
(osseous TISSUE) find a layer of cartilage. The adipose or fatty tissue is found immedi 
a'elv beneath the skin and in between the other tissues. Describe the appearance of 
muscular, n.-rvous.adinose, and cartilagenous tissues. What purposes are osseous,connective 
a .d epidermal tissue, made to serve? 

Properties and Uses of Tissues. Each tissue is made to Serve some 
definite purpose in the body. It is able to serve this purpose because of 
certain important properties which it possesses. Osseous tissue,for example, 
is hard, touch, elastic, stiff, and compact. On account of these properties 
it is used to form t he framework of the body, to protect delicate organs, and 
to form levers. Muscular tissue, likewise, has the remarkable property of 
contractility, on account of which, it is used in the body to produce motion. 
If the entire list of t issues were examined it would be found that each is 
peculiarly fitted for th • purpose it is made to serve. Show how connective 
tissue is adapted to its purpose in the body. 

Classes of Tissues. According to their purpose in the body, tissues are 
classed as supporting , active , storage and protective. The supporting 
tissues are those which hold the body together and form supports tor the 
more delicate p arts. Bone, cartilage, and connective tissues belong to this 
class. The active tissues are those through which the body expends its 
energy or does work. Muscular and nervous tissues are the most important 
members of this class. Storage tissues are those Which contain nourish¬ 
ment that the body may use at some future time. Of this class, fatty or 
adipose tissue is the best example. The best example of protective tissues 
are the epidermal and epithelial. The former covers and protects the out¬ 
side of the body and the latter the internal cavities to which the air 
penetrates. 


Composition of Tissues. The tissues are made up of minute particles, 
called cells. These are, for the most part, too small to be seen with the 
naked eye. In the body they vary in size from 1-4000 to 1-500 of an inch in 
diameter. They also vary in shape and general properties to suit their 
place in the body. A tissue is simply a collection of similar cells cemented 
together. Thee are therefoie as many kinds of cells in the body,as there are 
tissues. They are named according to the tisues which they help to form, 
muscular cells being found in muscular tissue, osseous cells iu osseous tissue 
and so on for the others. 


Structure of a Typical Cell. The outside part of the cell is usual¬ 
ly hardened forming the cell wall. This wall surrounds a transparent, jelly- 
like, substance cal led the protoplasm. Within the protoplasm is a denser 
part known as th ('..nucleus. In some cells there is yet a denser part of the 
nucleus called the nucleolus. Copy drawings. 




































V 





























































































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4 


Properties and Uses of* Parts. The cell wall is supposed to be form¬ 
ed by the hardening of the protoplasm on the outside. It protects the more 
delicate parts of the cell. The protoplasm resembles in appearance the 
white of a raw egg. When alive it is capable of a slight motion and is 
sensitive. It is able to absorb and appropriate liquid food and to grow. Itv 
is the living, active portion of the cell and is the one part which is absolute¬ 
ly essential. The other parts may be absent from the cell but never the 
protoplasm. The nucleus differs from the protoplasm in being denser. Its 
function is not fully understood, but it is supposed to give the cell the power 
of reproducing itself. Cells from which the nucleus is absent are unable to 
form new ones. 

Growth of Cells. The cells of the body, to a great extent, prepare 
the material for their growth from substances absorbed from the blood. 
These consistof various substances dissolved in water, forming a liquid food, 
and an active element obtained from the atmosphere called oxygen. With¬ 
in the cell, the oxygen and certain elements of the-liquid food unite. As a 
result of this union, heat is liberated, waste matter is formed, and new ma¬ 
terial, resembling the protoplasm, is produced. The heat beeps up the re¬ 
quisite warmth of the cell; the waste matter flows out into the blood; the 
new material is added to the cell and increases its size. 

Formation of New Cells. New cells are always formed from old 
ones. One process by which this is accomplished is called cell division. By 
this process a single cell will, after attaining its growth, separate into two 
or more new cells. (See drawing.) The new cells thus formed repeat the 
history of their parents, absorbing liquid food and oxygen, growing,and then 
dividing to form other new cells. 

Special Work of Different. Colls. There are certain kinds of work 
such as absorption, growth, and reproduction, which all the cells perform 
ir. common and by which they are individually benefited. In addition to 
this, each kind of cell has a special work to perform—a work which benefits, 
not only the cell itself, but the entire body as well. The special work of 
muscular cells is to cause motion; that of gland cells is to secrete liquids. 
Furnish other illustrations of the special work of cells. Like individuals 
working at different trades, the several classes of cells have specialized in 
some particular and have become able to do well one kind of work. Is this 

an advantage or disadvantage to the body? Compare “division of labor” as 
carried on by a community to thatcarried on by the cells in the body. 

Importance of the Cells. A knowledge of the structure, growth, 
and work of cells is the first step toward a clear understanding of the body. 
For the body grows by the growth and reproduction of its cells. All of its 
work is done by them. It is nourished and life maintained by nourishing 
and keeping alive the cells which compose it. The cell is thus the uuit of 
structure and function. 














































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6 


Organs. Tissues rlo not work singly but are grouped together forming 
organs. An organ is a part of the body which has some special work to per¬ 
form. The eye is an organ of sight. The hand is an organ for grasping. 
Name other examples. What different tissues are represented in the hand? 

Systems. Organs as a general thing, do not work singly, but are 
grouped into system®. A system may be said to be a collection of organs 
working together to accomplish some particular end or purpose. The heart, 
arteries, veins, and capillaries, for example, have for their common work 
the circulation of the blood and together they form the circulatory system. 
Supply other illustrations. 

The most imporantant systems of the body are as follows: 1. Digestive. 
2. Muscular. 3. Nervous. 4. Respiratory. 5. Excretory. 6. Cir¬ 
culatory. 7. Osseous.—State purpose of each of these systems. 

Tlie Maintenance of Life. This is the one purpose for which all 
the organs and systems of the body work. While the nature of life is, as 
yet, a great mystery, the plan of maintaining it in the bodies of animals is 
fairly well understood. Physiologically speaking, the life of the body may 
be regarded as the sum of the lives of the cells which compose it. Hence 
all effort at maintaining life must be directed toward the cells. By 
keeping them alive and active the body is kept alive. 

For the purpose of ministering directly to the wants of the cells, a 
liquid (the blood) is prepared and circulated thoughout the body. What do 
'.he cells receive from the blood? What does the blood receive from the 
cells? 

Certain of the systems do their part in maintaining life, by working for 
the blood. For,in order that it may discharge its functions toward the cells, 
it must be supplied with liquid food and oxygen, have its impurities re¬ 
moved, and be kept in constant circulation. What systems perform these 
services for the blood? 

Other systems help maintain life by working for the general welfare of 
the body, supplying it with food, clothing, and shelter, and guarding it 
against external danger. Copy and study the drawing. 

General Summary. The body is an aggregation of different kinds of 
cells. Like cells are grouped together forming tissues. The tissues are 
grouped into organs and the organs into systems. The systems are grouped 
to form tlie body, and all parts work together to maintain life. 

General Plan of the E xly. The body consists of a large central portion, 
the tmnk, to which is attached the head, arms, and legs. The arms, to¬ 
gether with the hands, are known as the upper extremities, while the legs 
and feet form the lower extremities. 

Within the head and trunk are three important cavities; the cranial, 
thoracic, and abdominal. The cranial cavity, located is the head,holds the 




Q 

brain while a downward extension through the spinal column contains the 
spinal cord. The thoracic or chest cavity, in the upper part of the trunk, 
supplies space for the heart and lungs. In that portion of the trunk below 
the chest is the abdominal cavity. It contains the liver, stomach, intes¬ 
tines, and other important organs and is separated from the cavity above by 
the diaphragm. Copy drawing. 

The outside of the body is covered and protected by the skin. The dif¬ 
ferent cavities are lined with membranes. The cavities which air can 
enter are lined with mucous membranes; those from which air is excluded 
are li jed with serous membranes. The lining membrane of the chest is 
called the pleura and that of the abdomen is called the peritoneum. 

A bony framework, the skeleton, gives form to the body and pio\ides 
support for the different organs. 

References: 


Review Questions. 1. Define Anatomy Physiology, and Hygiene. 2. 
How does Gross Anatomy differ from Histology? 3. What are “laws of 
health”? How is disobedience to them punished? 4. From what different 
sources may information concerning the body be obtained? 5. State 
objections to confining the study of the body to books. 6. Why call a 
tissue a building material? 7. Show that the use made of a tissue depends 
upon its properties. 8. Name an example of each of the different classes 
of tissues. 9. Draw a typical cell and name its parts. 10. Why is the 
protoplasm considered the most important part of thecell? 11. Howdo cells 
increase in numbers? 12. How does the body grow? 13. In what sense 
do the cells of the body practice “division of labor”? 14. De¬ 
fine and give illustrations of organs and systems. 15. How does keeping 
the cells alive keep the body alive? 16. What is liquid food? Illustrate. 
17. Name and locate the principal cavities of the body. 18. What cavities 
are lined with mucous membrane? What kind with serous? 










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The Blood. 


Two Liquids of similar nature are found in the body, known as the blood, 
and the lymph. The former is kept moving rapidly through a system of 
tubes called the blood vessels, while the latter moves slowly through another 

system of tubes called the lymphatics. Both minister to the wants of the 
colls. Packed away in the different tissues of the body, the cells have no 

way of procuring the materials needed for their growth and repair or of 
getting rid of the impurities which result from their activities. These 
liquids perform the double function of bringing to them the different ma¬ 
terials which they need and of removing their impurities. The study of the 
lymph and its special work will be deferred to a later period. 

Physical Properties of the Blood. 

Experiments. Secure through the assistance of a butcher two specimens of blood. 
One should be collected, without stirring, in a large open-mouthed bottle with straight sides, 
and kept in a quiet plan* fur one or two days. The other should be collected in a larger ves¬ 
sel for convenience, an empiv fruit can, and, while cooling, be stirred with a bunch of small 
switches. This process is called “whipping the blood” and its purpose is to prevent coagulation. 

Fibrin the coagulating agent, is thus removed as fast as it is formed. A portion of this de- 

flbrina'ted blood should be kept until it loses its oxygen and becomes a dark red color. 

a Examine tlie tir>t specimen to see the effect of coagulation. The central dark 
miss is called the cuot and the liquid surrounding it is called the sebum. The serum should 
appear nearly colorless. Sketch the vessel and its contents locating the two parts. 

b pour some of the deflbrinated blood upon the surface of water, in a glass vessel. 

Does it remain on the surface or sink to the bottom? What does this experiment prove with 
reference to the comparative weights of blood and water? 

c. Place a small amount of the dark, deflbrinated blood in a large test tube or bottle 
and thiri it by adding an equal amount of water. Then place the hand over the mouth of the 
vessel and shake until the blood is thoroughly mixed with the oxygen of the contained air. 
Compare with a portion of the blood not mixed with oxygen and notice any difference in 
color. What effect has oxygen upon the color of the blood? 

The above and other experiments show the blood to be heavier 
and denser than water; to have a faint odor and a slightly sweetish taste; 
to present a bright red appearance if it contains oxygen and a dark 
red if oxygen is absent; and to possess the power of coagulating. 

Coagulation refers to that property of the blood which enables it to 
thicken or clot when exposed to some unnatural condition. The cause of 
coagulation is fibvin — a clear, stringy, solid substance which, by its con¬ 
traction separates the corpuscles from the liquid portion of the blood and 
binds them into a mass, called the clot. Fibrin does not exist in normal 
blood ; but is formed as coagulation takes place. It is formed from materi¬ 
als which are always present in the blood known as th e fibrin factors. The 
conditions which induce coagulation must be such as will cause the fibrin 
factors to change into fibrin. Name some of these conditions. What im- 
nortant purpose is served by the coagulation of the blood? 







12 


Composition of the Elood. To the naked eye the blood has the appear¬ 
ance of a simple liquid. When examined with a powerful microscope, how¬ 
ever, it is seen to be made up of a clear, transparent liquid in which float 
great numbers of small, round bodies. The liquid portion is known as the 
plasma; the small bodies are called corpuscles. The corpuscles are of two 
kinds; the red and the white. 

Observation. Examine with a compound microscope, a small drop of blood taken 
from the finger by pricking it with a pin. Care must be taken to dilute it with a little water or 
saliva before putting on the cover glass,else the corpuscles will be too thick to be distinguish¬ 
able. If the specimen is to be viewed for a considerable length of time, a little oil should be 
run around the edge of the cover glass to prevent evaporation. All of the corpuscles seen will 
generally be of the red Wind, though occasional white ones may be found. These can be dis¬ 
tinguished from the red by their greater size and transparency. On account of the small 
amount of coloring mat er in each one, the red corpuscles do not appear red under the micro¬ 
scope. Make a sk-tch <>f the corpuscles as they appear under the glass. 

The Keel Corpuscles have the same general structure as cells, but there 
is an absence of any nucleus. In shape they are thin disks with concave 
sides. In size they vary from 1-8500 to 1-3200 of inch in diameter. In 
healthy blood they are exceedingly numerous, there being estimated to be 
as many as five million in a small drop of blood The function of the red 
corpuscles is to act as oxygen carriers. They absorb oxygen from the air 
at the lungs and give it up to the different cells of the body. They are en¬ 
abled to do this by the presence in them of a large proportion of a reddish 
coloring matter called 

Haemoglobin. This substance has the remarkable property of forming 
a weak chemical umon with oxygen and, after being united with it for 
a while, of giving it up to tissues which contain no oxygen. The haemoglobin 
also gives the red corpuscles their color. It is found attached to the wall 
of the corpuscle from which it may be separated, though slightly changed, 
by the following method : 

Cover a well washed elof of blood In a vessel, with alcohol. With a glass rod or clean 
piece of wood, worn the clot into as fine pieces as possible. Allow to stand over night. Tne 
clear reddish liquid contains the coloring matter ihat has been separated from the corpuscles. 
This may be poured off. without disturbing the bottom portion, and kept indefinitely in a 
well corked bottle. 

Origin of Hod Corpuscles. As the red corpuscles are constantly being 
destroyed in various ways, new ones have to be regularly supplied from 
some source to take their place. Their origin is not definitely known, 
though the best authorities now agree that a portion of them, at least, is 
formed in the red marrow of the bones. 

White Corpuscles. These are irregular in shape and about three times 
as large as the red ones. They are much less numerous, there being only 
about one white corpuscle for every 300 red ones. They are identical with 
the pus cells which are found in sores. They are able to change their form 
and pass through the walls of the capillaries into the tissues. (Copy draw¬ 
ing.) There are several varieties of these corpuscles and their work, as now 
understood, is to purify the blood by destroying disease germs. Thejy ar? 
formed chiefly in the lymphatic glands. 



































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14 


The Plasma consists of water with a great number of different sub¬ 
stances dissolved in it. It is therefore, a very complex liquid. The follow¬ 
ing important constituents may be named: 1. The fibrin factors which, 
by changing into fibrin, cause the blood to coagulate. 2. Substances which 
serve ns food for the cells. Chief among these are serum albumen, fatty sub¬ 
stances, and sugary substances. 3. Impurities from the cells, most import¬ 
ant of which, are carbon dioxid and urea. On account of the demands 


made upon the blood by the colls, the variety of foods eaten, and the dis¬ 
charge of impurities, the proportion of the constituents of the plasma is con¬ 
stantly changing. 

The serum is that portion of the plasma which remains,after the separa¬ 
tion of the fibrin factors. When does this separation occur? 


The chief constituents of the blood are represented by the following 
table : 


f Corpuscles 
Blood \ , 

Plasma j 


^ Red 
) White 

Serum . 

Fibrin Factors 


Water 

Serum Albumen 
Fatty Substances 
Sugary Substances 

S Common Salt 
Phosphate of Lime 
Carbonate of Lime 

T ... \ Carbon dioxid 

Impurities j Ucea 


Systems which Work for the Blood. That the blood may preform its 
double work for the cells, requires the combined action of several systems. 
Th e circulatory system keeps it moving through all portions of the body# 
The digestive system supplies it with liquid food. The respiratory system 
s applies it with oxygen . The excretory system relieves it of its impurities# 
State the necessity for the work which is done by each of these systems. 


References: 


Review Questions, l. What important work Is accomplished in the 
body, through the agency of the blood and lymph? 2. Compare the phys¬ 
ical properties of the blood with those of water. 3. How prove that oxygen 
changes blood from a dark red to a bright red color. 4. Name the principal 
constituents of the blood. Give use of each constituent. 5. What is 
haemoglobin? What is it able to do? What use is made of it? 6. Give 
composition of the plasma. How does it differ from the serum? 7. What 
is fibrin? When and for what purpose is it formed? From what is it formed? 
How does it differ from fibrin factors? 8. Compare red and white corpus¬ 
cles with reference to shape, size, number, origin, and function. 9. How 
may coagulation of the blood be hastened? How may it be prevented? 10. 
What are t he different systems of the body which work for the blood? 
































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Circulation of the Blood 


The hlood is, above all T a moving liquid. Its regular motion through 
the body—starting at one place, flowing out to the different parts and it* 

turning to that place—is termed the circulation. 

The discovery of the circulation of the b Y J was made in 1618 by a physician nan ed 
Harvey. In I6l!> he taught it iu his public lectures and in 1638 published the proofs. 
xjtijrie discoverv with reference to the human body lias proved of so great importance. * 
Knowiedte of the nature and purpose of the circulation was the necessary first step towaid 
a comprehension of the plan <>f maintaining life. Ilenoe Physiology as a science dates Iron 
the time of Harvey's discovery. 

TheNecessity for-tlic Circulation lies in the fact that the blood acts as 
a carrier for the cells. Oxygen from the lungs, and liquid food from the 
digestive organs, reach the cells through the blood. Likewise, the blood 
must convey the impurities from the cells to the organs of excretion. To 
accomplish these results the blood must move. So great is the necessity lor 
the circulation that its stoppage, for only a brief interval of time, results 
in death. 

The Organs of Circulation consist of a central force pump connected 
with a system of tubes which penetrate to all parts of the body. The four 
pump is called the heart, the tubes are called blood vessels. The blood 
vessels are of three kinds: Arteries , veins, and capillaries. 

Observation. Procure from the butcher shop the heart of ft sheep, calf, or hoc. 
To insure the specimen against mutilat ion, the lungs and diaphragm must be ordered left a • 
tachod to the h -art. In studying the diifere it par s, good results will be obtained by; observ¬ 
ing the following order of pro i * lure: 1. Observe the connection of the heart to the lungs, 
diaphragm, and large bl >o l vj>so.s. Inibre the lungs and observe the position of tiio heart 
with reference to them. £. Kx: unine outside of psricirdbim. then pierce Its lower portion 
and collect the pericardial fluid. Increase the opening thus made until it is large enough to 
;lip the heart out thro igh it. Slide back tiie pericardium until its attachment to the large 
blood vessels above the m art is found. 6. Trace out for ashort distance and study the veins 
and arte ies now expose I. Tne arteries are to be distinguished by their thick walls which ate 
elastic* like rubber. The veins have thin walls which are inelastic. The heart may now be 
severed from the lungs by cutting the large blood vessels, care being taken to leave a consid¬ 
erable length of each attached to the heart. 4. Observe the outer portion of heart. The 
thick 1 over portion contains the cavities called ventricles; the thin upper portion contains 
the auricles. The thicker and denser side lies toward the left of the animal’s bodv and is 
called the left side of the heart; the other is the right side. Locate the right auricle r.nrt 
the righi ventricle; the leit auricle and the left ventricle. 5. Make an incision into the right 
auricle la go enough to see t he inner portion. Observe muscular arrangement and inner sur¬ 
face. At i lie entrance into right ventricle find the tricuspid valve. 6. Lay open the right 
ventricle. Study tricuspid valve f *om. t’ie under side, noting its parts and tendinous attach¬ 
ments. Study mus ;ular arrangement and lining of the ventricle. Compare thickness of walls 
with those of right auricle. Find the opening into pulmonary artery. 7. Split open this? 
artery to where it enters the ventricle and find the right semi-lunaji valve. Of how many 
parts is it composed? 8. In like manner dissect the left side of heart. Compare the auri 
ido. ventricle, and valves, on this side, with similar parts on the right side of heart. 
















































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The Heart. By «onsuiting some Physiology ascertain the shape, size, 
and location of the human heart. Name ana describe its outer and inner 
coverings. Locate and name itscavities, valves,and the blood vessels connect¬ 
ed with\t. Copy drawing from chart, locating and naming pirfcs. Practice 
on this drawing until you can reproduce it from mmi.ry. Wait is the 
special work of the auricles? Of the ventricles? Of the valves? Account 
for the fact that the walls of the ventricles are thicker th in those of the 
auricles; that the walls of the left ventricle are thicker than those of the 


right. 

How the Heart Does Its Wort. The heart is a hollow muscle and does 
its work by contracting and relaxing. When it contracts its cavities are 
closed and the blood is forced from them. When it relaxes the cavities 
open and the blood flows in to refill them. Valves prevent the backward 
flow of blood. How? The heart’s action maybe readily illustiated in the 

following manner: . . J . 

Kit valves into the two ends of a rubber tube, six inches long and an inch in diameter. 

so that they open in the same direciion. The valves are easllv prepared by burning or filing a 
smooth round hole through each of two corks which just fit the tube. Place over the opening 
in each cork, a thin flap of rubber or leather and secure in position by pushing a pin through 
it into the cork Tho valves thus formed may be inserted in .the tube as directed. 
Now if the end of the tube containing the entrance valve, be placed In water and the body of 
the tube alternately compressed and released by the hand, water will flow up through it. What 
action of the ventr.cles is represented by compressing the sides of the tube? What by releas- 

th ° /^connecting the ends of the pump with rubber tubes whicli can be filled with water 
an 1 c mnected with each other, the entire circulation may be illustrated. 


Arteries and veins. These are cylindrical tubes, connected with the 
heart, through which the blood passes. The arteries receive the blood 
from the ventricles and permit it to pass through them and their branches 
to nil parts of the body. In its return to the heart the blood passes through 
the veins. Although arteries and veins are quite similar in structure they 
have some important differences. From some text on Physiology, ascertain 
how they differ with reference to thickness and elasticity of walls, the 
presence of valves, the kind of blood which they carry, and the nature 
of the flow of blood through them. 

Through the elasticity of the arteries, the intermittent flow of blood, 
caused by the heart’s action, is changed to a constant flow in the capillaries. 
When the ventricles contract and blood is forced into the arteries, they are 
tilled over-full and have to swell out to make room for the excess. Then, 
while the ventricles are relaxing, the arteries exert their elastic force against 
the blood. The result is to keep the blood under constant pressure -in the 

arteries and to cause it to flow steadily through the capillaries. The elas¬ 
ticity of the arteries is thus made to serve the same purpose in the circula 
tinn, as that served by the air chamber in force pumps 

The purpose of the valves in the veins is to enable muscular contraction 
to assist in propelling the blood. When muscles contract they press against 















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the sidesof the veins,p issing through'them,and tend to empty them at that 
place. Since the valves open in the direction of the flow of the blood, they 
will be closed by any backward motion. The force of muscular contraction 
is thus made to push the blood forward. 

The Capillaries consist of a network of very fine blood vessels which 
connect the terminations ■ f the smallest arteries with the beginning of the 
smallest veins. With a few exceptions, they penetrate and permeate all 
parts of the body. They differ from both arteries and veins in being very 

small and in having very thin walls. It is the function of the capillaries to 
bring the blood as near as possible to the individual cells so that the ex¬ 
change of material between the blood and cells may readily take place. How 
is this exchange made easier by the small tubes and the thin walls? 

Observation. With a compound microscope examine the flow of blood through die 
capillaries of the tail of a live tadpole To ho d the specimen in position and prevent its ba¬ 
ling too dry, attacli it to the slide wi h a narrow strip of wet cloth, matting several loose 
turns completely around bo'li the spocimen and slide. C ire must be taken not to stop the 
circulation by toogreat pressure. A tadpole, recently caught and more than an inch in length, 
will ire the best results. The observer will aecouut for the seeming great rapidity of the 
m vi ig stream by remembering that the microscope also magnifies the motion of the blood. 

The Circulation Traced. The blood in making its double circuit passes 
through the circulatory organs in the following order: Right auricle, tri¬ 
cuspid valve, right ventricle,right semilunar valve, pulmonary arteries, capil¬ 
laries of lungs,pulmonary veins, left auricle,mitral valve, left ventricle, left 
semilunar valve, aorta and branches, systemic capillaries, veins, vena cava as¬ 
cending and descending, and then again into right auricle. At the lungs th<f 
blood gives up carbon dioxid and receives oxygen. In the systemic capillar 
ies it gives up its oxygen and receives carbon dioxid and other impurities. 

Divisions of Circulatory System. The circulation of the blood through 
the lungs is called th & pulmonary clrculation^thiough the body, the systemic^ 
through the liver,the portal ; through the kidneys, the renal-,amd through the 
heart itself, the coronary circulation. 

Health Suggestions. The vigor of the circulatory organs is largely de¬ 
pendent upon one’s habits of living. Perhaps no one thing benefits them 
more than regular physical exercise. Not only does muscular work assist 
in propelling blood through the veins, but is an important means of 
strengthening the heart’s action as well. Violent exertions, on the other 
band, endanger the circulatory organs and should be avoided. The effect 
of many stimulants, especially alcoholic drinks, is to interfere with the 
action of these organs and to diminish their vigor. Tight fitting 
clothing, on any part of the body, interferes with the free circulation and, 
for this reason, should not be worn 


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22 


Review Questions, l. What is accomplished in the body by the circu¬ 
lation of the blood? 2. Name the different kinds of circulatory organ's and 
give use of each. 3. Draw a diagram of the heart, naming and locating the 
cavities,valves,and the large blood vessels connected with it. Indicate by ar¬ 
rows the direction of the flow of blood through the different parts. 4. Explain 
how the heart does its work. 5. Of what advantage is the elasticity of the 
arteries? 6. What purpose is served by the valves in the veins? 
7. What is the special work of the capillaries? 8. Trace the blood from 
the right auricle, through the different circulatory organs, back to that 
place. 9. What causes the “pulse” in arteries? Why does the blood flow 
in spurts from a cut artery? 10. How are the organs of circulation affect¬ 
ed by moderate physical exercise? How by excessive exercise? How by 
alcoholic drinks? 11. Give directions for stopping the flow of Tood from 
wounds. 



The Lymph and the Lymphatics. 

Tlie Lymph lies outside the capillary walls arid fills up such spaces as 
exist between the cells of the different tissues and between the cells and the 
walls of the capillaries. The blood, it will be remembered, flows in closed 
tubes and does not come in direct contact with any of the tissues. Oxygen 
and liquid food pass from the blood through the lymph to get to the cells, 
while impurities from the cells pass through the lymph to get to the blood. 
The lymph is thus the medium through which the exchanges, between the 
blood aud the cells, take place. 

The chief Source of the Lymph is the escape of the blood plasma at the 
capillaries. Partly on account of the pressure on the blood in the capillaries 
and partly on account of the natural tendency of liquids to pass through 
animal membranes, a considerable portion of the plasma penetrates the 
thin capillary walls and enters the spaces occupied by the lymph. Another 
source, of less importance, is the absorption of liquids from the alimentary 
canal. Liquids absorbed through the skin, on the outside of the body, also 
become a part of the lymph. 

The Composition of the Lymph is quite similar to that of the blood. In 
fact, all the important constituents of the blood are found in the lymph,but 
in different proportions. Food materials for the cells and fibrin factors, ex¬ 
ist in smalltr proportions than in the blood; impurities from the cells, in 
larger proportions. The per cent of white corpuscles is slightly greater 
than in the blood, while there is nearly a complete absence of red corpus¬ 
cles. 










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24 


Physical Properties. The lymph is a colorless liquid slightly heavier 
aud denser than water, though not so dense as the blood. It has no well 
defined odor or taste. Like the blood, it has the power of coagulating. 

Movements of the Lymph. Though the lymph may be regarded as a 
comparatively quiet liquid, it has three well deflned movements as follows: 
1. A current which passes through it from the capillaries toward the cells. 2. 
A current from the cells toward the capillaries. 3. A movement of the 
entire body of lymph along the lymph channels, toward the larger lymph 
vessels.—The distinct and well deflned lymph vessels are called the 

Lymphatics. These vessels, though small, are exceedingly numerous iD 
most parts of the body. Their walls are very thin and easily compressed, 
and all but the smallest are supplied with great numbers of valves. From 
the different organs of the body they gradually converge toward two main 
tubes. One of these, the right lymphatic duct, empties into the right 
subclavian vein. The other,the thoracic duct, empties into the left subclavian 
vein. (Copy drawing.) Lymph from the right side of the head, right arm, 
and right side of chest, passes into the blood through the right lymphatic 
duct. Lymph from the lower extremities, abdomen, leftside of chest and 
iiead, aud left arm, passes into the blood through the thoracic duct. 

Functions of the Lymphatics. 1. They help enclose a quiet liquid (the 
lymph) which assists in the exchange of materials between the blood and the 
cells. 2. They return the plasma which escapes at the capillaries to make 
lymph, to the blood vessels. 3. They act as absorbing vessels in the 
skin and digestive organs, those absorbing from the small intestines being 
known as the lacteals. 

Lymphatic Glands. Connected with the lymphatic vessels are great 
numbers of small glands, known as the lymphatic glands. As to the 
structure of these bodies and their connection with the lymphatics, there is 
a difference of opinion among physiologists. About all that can be said of 
their function is that they assist in the formation of white corpuscles. 

Causes of Flow of Lymph. There is no force pump, like the heart, con¬ 
nected with the lymphatics and the causes of the flow of lymph are some¬ 
what obscure. Blood pressure on the lymph at the capillaries and the con¬ 
traction of muscles against the walls of the lymph vessels are supposed to be 
the chief causes. (Copy and explain drawing.) 


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Review Questions, l. What position, with reference to the capillar¬ 
ies and the cells, is occupied hy the lymph? 2. What is the purpose of the 
lymph? 3. Compare the blood and the lymoh with reference to composi¬ 
tion, physical properties, and movement through the body. 4. Compare 
t'he lymphatics and the blood vessels with reference to size, number, and 
kinds. 5. What different purposes arc served by the lymphatics? 6. How 
does muscular contraction cause the lymph to flow? 7. Trace the lymph, 
in its flow from the right hand, to where it enters the blood. Trace it 
from the feet to where it enters the blood. 8. Wtat are lacteals? What 
purpose do they serve? 


-: o :-- 

Osmosis. 

Osmosis, or dialysis, refers to the passage of liquid substances through 
animal membranes. If a vessel, with an upright membranous partition, be 
filled on one side with water containing salt, and on the other side with 
water containing sugar, an interchange of material will take place through 
the membrane until the same proportion of salt and sugar exists in the 
separated liquids. 

Experiment. Separate the shell from the lining membrane, at one end of an egg, over 
an area, an inch in diameter. To do this without Injuring the membrane, the shell must be 
broken into small pieces, which may be picked off with a pair of forceps. Fit a small glass 
tube, 8 inches long, intolhe oilier end, so that it sha 1 poneirate the membrane and pass down 
into the yolk. Securely fasten the tube to the shell with beeswax, and set the qgg in a small 
tumbler partly tilled with water. Examine fn the course of half an hour. What evidence 
now exists to prove that water has passed through the iiiembrqne'into the egg? What to show 
that a portion of the egg has passed into the water? YVhioh way has the flow of liquid been 
the greater? 

The Conditions under which Osmosis occurs are as follows : 1. The 

liquids on the two sides of the membrane must be unlike cither in compo¬ 
sition or density. In case of a difference in density the greater flow of 
liquid is toward the denser substance. 2. Both liquids must be capable 
of wetting or penetrating the membrane. If but one liquid wets the mem¬ 
brane, the flow will take place in but one direction. 8. The liquids must 
have enough attraction for each other to mix readily. 

Application. The many interchanges of material between different 
portions of the body are now understood to occur in accordance with the 
laws of osmosis. The exchange of material between the blood and the 
lymph,and the lymph and the cells; the exchange of gases at the lungs; 
and the absorption of liquids from the alimentary canal,furnish perhaps the 
best examples. 

Problem: Show what conditions must exist, in order to cause a continuous flow of 
oxygen and food substanoes from the blood, through the lymph, to the cells: to cause a con¬ 
tinuous flow of impurities in tue opposite direction. 


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Respiration. 


Respiration, or breathing, is carried on by alternately taking air into 
and expelling it from the lungs. The former act is called inspiration; the 
latter expiration. Through respiration the blood is supplied with oxygen 
and relieved of certain impurities, principally carbon dioxid. 

The Respiratory Organs consist of the air passages, respiratory mus. 


cles, and ribs, as shown by the following outline: 

f Nostrils and mouth 
Pharynx 
Larynx 

,. | Trachea 

Air passages - Br(>richi 

Bronchial tubes 
| Lesser bronchial tubes 
I^Air vesicles 


Respiratory Organs -j Ribs 


External 

Internal 


( Elevators of ribs 

Muscles ^Intercostal. 

( Diaphragm 

Observation. Secure from a butcher the lungs of a sheep, calf, or hog. The wlnft- 
pipe and heart should be left attached to the specimen, which must be kept in a moist con¬ 
dition until used. Study in the following order: 1. Examine the large open tube (traohea) 
and the closed tube lying back of it (oesophagus). Observe the cartilagenous rings in the 
trachea What purpose do they serve? Remove one and make a drawing of it. 2. Insert 
a tube in the trachea and inflate the lungs. About how many times is their volume thus in¬ 
creased? 3. Examine the thin membrane (pleura) enclosing the lungs. Test its elasticity. 
4 Sevor the smy’lest lobe fiom the lemainderby cutting the bronchial tube. Split this 
tube a short distance into the lung, observing its smooth lining and the openings of smaller 
tubes branching off from it. Are the rings in these lubes circular or like those in the traohea? 
Make cross sections of this portion of the lung and find the openings of the lesser bronchial 
tubes. 5. Follow the trachea down to wh “ro it branches to form the bronchi. Find a branoli 
of the pulmonary artery which approaches one of trie bronchi and cut both artery and 
bronchus from their connections Now trace the bronchus and artery into the lung. Observe 
that as one branches, the other brancm s until the smallest divisions are reached. The 
pulmonary veins also lie alongsi ie the bronchial tubes, but are not as easily traced as the 
arteries. Why? 6. Place a piece of lung upon water. In floating, what proportion of it is 
submerged. Inference. 


The Air Passages form a continuous path for the entrance and exit of 
the air. By what kind of membrane are they lined g Name the different 
passages in the order that air goes through them, during inspiration: dur¬ 
ing expiration. The bronchial tubes, lesser bronchial tubes, and air ves¬ 
icles, together with their conncciive tissue,blood vessels,lymphatics, nerves, 
and membranes, form the lungs. In order that the air may move freely 
through the different passages it is very necessary that they be kept open 
and clean. 

















































The Air Passages are Kept Open, by special contrivances found in their 
walls. In the trachea, bronchi, and larger bronchial tubes, these consist of 
imperfect cartilagenous rings. In the smaller tubes the rings disappear 
and their place is supplied by connective tissue. On account of the stiffen¬ 
ing material in their walls, the size of the air tubes does not change as the 
air moves through them; but the air vesicles collapse when the air leaves 
them. 

How the Air Passages are Kept Clean. This work is done by the cells 
which 1 i qc the greater portion of the mucous membrane of the air passages, 
known as the ciliated epithelial cells. (Copy drawing of these cells from 
chart.) Extending into the air passages from the ends of these cells, are 
numerous hair-like projections called cilia. These keep up an inward and 
outward wave-like motion which has greater force in the outward direction. 
The effect of this motion is to carry any foreign matter to where it ca.i be 
expelled from the passages. Even a slight cold on the lungs might prove 
fatal were it not for these cells. Why? 

The Air Vesicles are the small membranous sacs found at the ends of the 
smallest bronchial tubes. They are about 1-100 of an inch in diam iter and 
a cluster of them is found at the end of each bronchial tube. Each is com¬ 
posed of a lining of thin, flat cells, resting upon a delicate support of con¬ 
nective tissue which is very elastic. In these tiny sacs the air conrm.s near¬ 
est the blood, giving up its oxygen and receiving carbon dioxid. But 
it does not come in direct contact with the blood. Within the 
walls of the vesicle is a network of capillaries, through which the blood 
flows. The exchange of gases takes place through the capillary walls. 
(Copy drawing.) 

The Thorax is the air-tight, cavity which contains the heart and lungs. 
It is enclosed on its different sides by the ribs and spinal column. It is 
separated from the abdomen by a strong muscular partition called the dia¬ 
phragm. Between the ribs lie the intercostal muscles. By means of the 
diaphragm and the action of the intercostal muscles on the ribs, the size of 
this cavity may he changed. The thorax fs lined with a thin, elastic mem¬ 
brane called the 

Pleura. The pleura forms a double, closed sac, one side of which is at¬ 
tached to the lungs and the other to the chest walls. A thin membranous 
partition divides the thorax into two parts and the pleura surrounds the 
lungs so as to cause each half to hang in an air-tight sac. (Copy 
drawing.) It secretes a fluid which keeps it moist and prevents friction. 
What is pleurisy? 

How Air is Brought into and Expelled from the Lungs. The atmosphere 
which surrounds us on every hand, exerts a pressure against objects of 
nearly 15 pounds to the square inch. It is this pressure which enables us to 










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breathe. Air enters and is cxpelcJ from the lungs for the same reason 
that it flows into and is forced out of a pair of bellows. | 

Experiment. Ex train; ;i pair of hand bellows, such as is used in kindling iircs. If 
the sides are spread apart, th < air tt >ws into them: when they are pressed together, the air 
is forced out. Why ? Spre iding apart the sides of the bellows increases the soace within 
an 1 forms an area of less i>rets .re than that on the outside. Air from the outside is then, 
forced in, until the equ Uity of th • pressure is restored. When the sides of the bellows are 
fore id t igether, the pressu. - e within heoo nes greater than tnat on the outside. What then 
happens? 

In breathing, the air-tight thorax takes the place of the bellows. By 
the action of the muscles its size is alternately increased and diminished. 
The lungs are suspended in the thorax with but a single opening—that 
through the trachea. What will happen when the thorax is enlarged? What, 

when it is diminished in size. Try the following 

Experiment. With a tape line, lake thecireumference of the chest of a hoy, when he 
has all the air possible expelled from the lungs Take It again when he has them inflated to. 
their utmost capacity, rhe difference in the measurements represents his relative chest 
capacity. What does this experiment show with reference to the cause of breathing? 

How the Thorax Changes its Capacity. The capacity of the thorax is 
increased by the elevation of the ribs and the depression of the diaphragm. 
The former process increases the transverse diameter: the latter the longi¬ 
tudinal. The ribs are raised mainly by the action of muscles attached be¬ 
tween them and the spinal column, called the elevators of the ribs, and by 
the outer set of intercostal muscles. The diaphragm being naturally in an 
arched position, it is depressed by its own contraction. As it lowers 
it pushes down the contents of the ai d mien. Describe diaphragm. 

Experiment. With five narrow strips <>f cardboard, one 8 Inches long and the 
others 6 inches, construct a fig' ire to represent the thorax. Let the long strip serve as ilie 
spinal column and one of the short ones as the bre ist bone Fasten the others between 
them for ribs The fastenings which mu it admit of motion, may be made by simply pushing 
pins through the strips where they join. 

Holding the piece representing the spina’ column in a vertical position, raise and 
lower the piece representing ihe breast bone. Wnen is the space between the upright pieces 
the greatest? Apply to the action of the ribs in inere ising the thoracic cavity. 

The capacity of the thorax is diminished by lowering the ribs and 
elevating the diaphragm. Ordinarily the ribs are lowered by their own 
weight. In forced expiration the internal intercostal muscles are brought 
into play. The diaphragm is pushed up by the contents of the abdoman, 
which are pressed upon by the contraction cf the abdominal walls. (Copy 
drawing fiom chart.) 

Health Suggestions. One should breathe pure air in sufficient quanti¬ 
ties. Pure air is,of course,found out of doors. It may be obtained indoors if 
attention is paid to the proper ventilation of rooms. The plan of heating a 
room will,to a large extent, determine the plan to he followed in ventilating 
it. In rooms where the air is not heated before being admitted, great care 
should be exercised to avoid drafts. For this reason, the air should be 
allowed to enter at several small openings instead of a few large ones. 

Pitoni.KM: Suggest a plan for ventilating a school room, 50 ft. in length by 30 ft. in 
width, which has a sr, ve near the middle and three windows on each side. In what kind of 
weather will the openings to admit air need to be large? Whoa small? Why? 















































* . • 







36 


The quantity of air which one is able to breathe, is determined by his 
chest capacity. To keep this at its maximum, the following habits should be 

observed: 1. Take plenty of active exercise in the open air. 2. Practice 

occasional deep breathing. 3. Sic and stand erect with shoulders thrown 
back. 4. Wear loose lilting clothing arouud the chest and waist. 

References: 


Review Questions: 1. Of what two ptocesses does respiration consist? 
2. State the double purpose of respiration. 3. Name the air passages in 
the order that they are connected. 4. How are the air passages 
kept open? How are they kept clean? 5. Of what are the lungs 
composed? 6. Why are the lungs son e atnes called •‘lights”? 7. Des¬ 
cribe an air vesicle. What takes place in it.’* 8. What has atmospheric 

pressure to do with breathing? 9. Compare the action of the thorax to that 
of a pair of bellows. 10. How is the size of the thorax increased? How dimin¬ 
ished? 11. Why are you unable to expand the chest when the mouth and 
nostrils are closed? Tryit. 12. What causes the air in an occupied room to be¬ 
come impure? 13. What is meant by chest capacity? 14. Why will 
active exercise tend to increase the chest capacity? 15. How does com¬ 
pressing the waist diminish the chest capacity? 

The Atmosphere. 

The Atmosphere is the gaseous envelope, surrounding the earth, in 
which we “live, move, and have our being.” A slight knowledge of it 
is necessary, in the study of physiology, since a portion of it is consumed by 
the body in maintaining life. It is a mixture of colorless gases, nearly 
four-fifths being made up of nitrogen and one-fifth of oxygen. In addition 
to these it contains a small amount of carbon dioxid and a variable amount 
of watery vapor. We are especially concerned with oxygen and carbon 
dioxid, for by respiration, the former is given to the blood, and the latter 
removed from it. 

The Gas Oxygon is remarkable for its strong attraction for other ele¬ 
ments, especially carbon and hydrogen. On account of this attraction 
it unites readily with different substances to form compounds and is said to 
to be a very active element. With certain substances it unites so rapidly 
that heat and light are given off. This rapid uniting we call burning or 
combustion. 

Experiments. Prepare oxygen by heating together equal quantities of potassium 
chlorate and manganese dioxid For method of collecting the gas consult some text on 
chemistry. In the following experiments four large-mouthed bottles of gas are required. 
Care must be taken to keep the bottles closed, in order to prevent escape of the gas. 

a. Insert a burning splinter in a bottle of oxygen and observe change in the color 
and size of ibe flame. Removequickly and extinguish the flame, leaving only a spark on the 
end of the splinter. Insert a second lime in the oxygen. The spark should burst into a flame. 

b. Attach apiece of charcoal, or carbon, to tiie end of a wire. Hold in a hot flame 
until the carbon begins to glow and then Insert in th- oxygen. Leave there until the burning 
ceases. Observe that a portion of the carbon aud all the oxygen has disappeared. What 
has become of them? 




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c. Remove the remaining carbon and pour some coloi-less Urn"* wafer into the bottle. 
If mixed with the gas in the bottle by shaking, the lime water will turn a m Iky white color. 
This proves the presence of a new substance in the bottle. It is caiibon dioxid and it has 
been formed by the uniting of the carbon and the oxygen. 

d. Bend a small loop on the end of a piece of picture wire. Heat the loop in a hot 
flame and then insert in some powdered sulphur. Ignite the melted sulphur which adheres 
and insert it quickly in a bottle of oxygen. Does the wire burn with a flame? Observe the dark 
brittle material which is formed. It is a compound of oxygen and iron, sim lar to iron rust, 
and has been formed by their uniting. 

Purpose of Oxygen in the Body. The purpose of oxygen in the body is 
to produce a continuous series of chemical changes which shall liberate 
heat and supply the force with which the b.-dy does its work. It produces 
these changes by uniting with the different constituents of the liquid food 

in the cells and in some instances with the cells themselves, to form new 

substances. Since life depends directly on the continuance of these changes, 
oxygen is said to be the supporter of life. 

The new materials which result from chemical unions in the cells are of 
two kinds: Those which can be used in cell growth, and those which form 
the waste and have to he removed. One of the most important waste ma¬ 
terials thus formed is 

Carbon Dioxid. This substance is formed by the union of oxygen with 
the carbon of the food materials in the body. It is a gas. heavier than air, 
which extinguishes flame and, in large quantities, is injurious to animal 
life. It is removed from the atmosphere by plants and serves an important 
purpose in their growth. The test for carbon dioxid is lime water with 

which it unites to form carbonate of lime. 

Experiments Prepare lime water by stirring a small amout of frksh lime in water 
and allowing it to settle. The el ar liquid above the lime, is lime water It mar be poured 
ofl okI used, while the vessel containing the lime may be filled again with water for future 

supplies. fhe breath through a small tube into lime water in a tumbler. The lime water 

turns a rnilRv white color. Wliar does this prove to be present in the breath? 

b. Burn a splinter in a large bottle, keeping the top covered. Then pour in a little 
lime water and shuke observe and account for the result. 

c Pour a Pttle hydrochloric acid over some pieces of limestone in a bottle. A gas is 
is liberated which fills the bottle. It is carbon dioxid. 1. Insert a burning spinner in the gas 
and observe the effect. 2. Tip the ho'tie over the mouth of a tumbler as you would to emptv 
it, of water, though not far enough to soill the acid. Now insert tbe burning splinter in the 
tumbler and account for what happens. What is proven with reference to the weight of the 

l?a8t d Fill a quart jar even full of water. Place a heavy piece of cardboard over its 
mouth and invert, without spil'ing, in a pan of water. Inserting a tube under the jar, 
blow air that has been held a short time in the lungs, into it. Remove the jar, when 
filled with air, from the pan. but keep the top well covered. 1. Insert a burning splinter and 
observethe result. This proves tbe absence of what? 2. Pour in a little lime water and 
shake. Account for the result. 

e. Blow the breath against a cold window pane and account for the result. What 
does this show the breath to contain? Why must the window pane be cold i 

References: 

Review Questions. 1. What is the purpose of oxygen in the body? 2. 
How does it cause chemical changes? 3. Why are chemical changes 
necessary to life? 4. Why is oxygen so well adapted to producing chemical 
changes? «. What is formed when oxygen unites with carbon? When it 
unites with iron? 6. Hive some of the properties of carbon dioxid. What 
becomes of it after it escapes into the air? 7. What changes does the air 
undergo while in the lungs? 


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Digestion. 


General Statement. Digestion is the process by which food material is 
prepared for the blood. Since nothing but liquids can enter the blood 
vessels, digestion must consist, to a large extent, in the reduction of solids to 
the liquid state. This is accomplished by dissolving them in certain 
liquids which are prepared for this purpose by organs called glands. Name 
one of these liquids and the glands which secrete it. With reference to the 
changes they have to undergo, during digestion, foods may be divided into 
three classes: 1. Substances already in the liquid state. Name one. 
These require no digestion, but are ready, at once, to be taken into the 
blood vessels. Oils and milk are exceptions to this class. 2. Foods which 
are soluble in water. Furnish examples. These require only to be dissolved. 
8. Substances insoluble in water. The first step in the digestion of these 
is to change them into substances which are soluble in water. This class 
contains the greater number of our solid foods and includes albuminous 
substances, starches, and fats. 


Experiment. Procure three tumblers. To the first add some water; to the second, a 
teaspoonful of fine salt; and to the third, some small pieces of limestone. Over the salt, in the 
second tumbler, pour some water, and over the limestone pour hydrochloric acid. Observe 
the effect in each case. What finally happens to both the solid substances? 

As regards solubility, the substances in the tumblers will represent the three classes of 
food. The water, being a liquid, requires do change. The salt, a substance soluble in water, 
is readily dissolved by the water. The limestone, which is insoluble in water, is changed 
to a soluble substance «>hteh is dissolved by the water in the acid. 

The Organs of D gestion are of three kinds: 1. Those for crushing 
and grinding the food- 2. Glands to secrete the liquids which act upon 
the food to change it chemically and dissolve it. 3. Cavities in which the 
different processes of digestion take place and tubes connecting them. The 
cavities and tubes are connected to form one continuous canal This begins 
at the mouth and extends entirely through the body and is culled the 
alimentary canal. The parts of this canal and the different glands are 
shown by the following table: 


Digestive 

Organ,' 


I Ugcstive 

Glands 


Parts of 
Alimentary 
Canal 


f Salivary.. 

Gastric 
\ Liver 
Pancreas 
Intestinal 
Mouth, containing 
Pharynx 
Oesophagus 
Stomach 


Parotid 

Submaxillary 

Sublingual 


Teeth and 
Tongue 


Intestines.. - 


( Duodenum 
Small < Jejunum 
( Ileum 

f Coecum and Vermi- 
| form Appendix 
Large -j ( Ascending 


Colon.. 
(_ Rectum 


Transverse 

Descending 

















42 


The Alimentary Canal, p. different individuals, varies in length from 2> 
to 30 feet- The greater portion of it is made up of three distinct layers of 
substance called eoats. (Copy drawing ) The oesophagus and the pharynx 
have only two coats. The inner coat consists of mucous membrane; the 
middle coat is .oscular: the outer co ir is a serous membrane, being a con¬ 
tinuation of the lining of the abdominal cavity, called the peritoneum. 
Another coat is sometimes described, called the submucous, which lies be¬ 
tween the mucous and muscular. 


Tlie Mucous Membrane, semdimes called the inner sltin. is 11 lee the 
skin on the outside of the body in having tw > distinct layers of substance. 
The lower layer is the thicker and contains many blood vessels, nerves, 
and glands. The upper layer consists principally of tough non-sensi¬ 
tive epithelial cells. These protect the walls of the canal against 
the action of the digestive fluids. A fluid called mucus is secreted 
which keeps the membrane moist and soft. In di Jercnt parts of the canal 
the mucous membrane presents different appearances. That of the mouth, 
pharynx. cesophagas. and large intestine is smooth. In the stomach it con¬ 
tains a number of longitudinal folds which greatly increase its surface and 
furnish additional room for the gastric glands embedded within it. In the 
small intestine it has a soft velvety appearance due to the presence of large 
numbers of absorbent vessels called the villi, and its surface is much in¬ 
creased by transverse folds or ridges- These retard the motion of the food 
through the small intestine and provide more surface for the villi- 

Work of the Alimentary Muscles. The mechanical part of digestion is 
accomplished by muscles- These encircle the alimentary canal and, for 
the most part form the middle coat. Around the month they are attached 
to the jaws and furnish the power for masticating the food. The tongue is 
a muscular orran which pushes the food around in the mouth during mas¬ 
tication and lorees it back into the pharynx, when it is to be swallowed. 
The muscles of the pharynx and (.esophagus force the food from 
the mouth into the stomach. Those of the stomach are arranged in 
three distinct layers which pass around it in different directions. By alter¬ 
nately contracting and relaxing they serve to mix the food with the gastric 
juice. How'? Around the opening of the stomach into the duodenum, is a 
thick, muscular band which is contracted during stomach digestion, 
and is relaxed at other times. State its purpose. The muscles of the large 
and small intestines push the food along through the canal and finally force 
the undigested portions out of the body. The motions of the stomach and 
intestines caused by their muscles, are called the peristaltic movements. 
What muscles of the alimentary canal are voluntary? What are involun¬ 
tary? 
























































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Parts of Alimentary Canal .— 

Since information commriiinjr tlie structure and function of the parts of the canal is 
easily obtained from the usual texts on Physiology, only the plan of their study is here in¬ 
dicated. 

The Mouth is an irregular cavity at the beginning of the canal. Give 
three of its uses- Name its boundaries. How is it separated from the 
pharynx? How may its size be varied to suit its contvnts? Most of the 
space within the mouth is usually taken up by the tongue and 

The Teeth. The parts of a tooth are croton, neck ,and fang. Represent 
these parts by a drawing. A tooth is made up of enamel, dentine, pulp, and 
cement. Give properties and uses of each substance. Show by a drawing the 
position of each in the tooth. Name, locate, describe, and give use of the 
different kinds of teeth. What set of teeth is called permanent? What 
temporary? How many in each set? State two functions of the teeth. 
Give directions for care of teeth. When should the dentist be consulted? 

The Tongue is a muscular organ which has its fibres running in every 
direction. It is thus able to assume a great variety of shapes. (Copy 
drawing.) At its base it is connected with hyoid and submaxillary bones. 
Name two uses of the tongue. 

Pharynx. This cavity is the cross roads of the air tract and the food 
canal. It lies back of the mouth and has seven different openings. Name 
them. (Make drawing showing its position and connections.) How is it 
separated from the mouth? What is its work in swallowing? Are its mus¬ 
cles voluntary or involuntary? 

Oesophagus. What is its length? With what is it connected? De¬ 
scribe its coats. Does the food fall from mouth into stomach, or is it forced 
down? Give proofs. 

Stomach. Give its shape, size, location, openings, and coats. Describe 
its two orifices. Compare with other digestive cavities with reference to 
size. What glands does it contain? Where do they lie? Describe muscles 
of stomach? What is their function? 

Small Intestine. Name and locate its parts. Give its length and diam¬ 
eter. What coats has it? Describe its mucous membrane. How is so 
long a tube able to accommodate itself to the cavity in which it lies? What 
is the messentaryf What are its uses? 

Large Intestine. Give its length and name its parts. At its beginning 
there is a sort of pouch, or sac, called the coecum, into which the small in¬ 
testine empties by the ilco-coccal valve. At the bottom, the coecum ex¬ 
tends into a very narrow projection called the vermiform appendix which 
is not only an organ without a function, but is often a source of disease. 
(Copy drawing showing connection of the coecum with the small intestine 
and appendix, naming the parts.) 










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46 


Glands .—• 

Glands are found in many parts of the body, their function being to 
secrete liquids. The liquids, thus formed, serve different purposes, those of 
the digestive organs being to dissolve the food. The materials which form the 
liquids are obtained from the blood, but are supposed to undergo a change 
as they pass through the glands. The principal constituent of all the diges¬ 
tive fluids is water. 

General Structure of Glands. All glands have the same essential 
parts. These are: 1. A layer of gland or secreting cells. 2. A thin 
layer of connective tissue, called the basement membrane. 3. A network 
of capillaries very near the cells. 4. A system of nerve fibres.—The gland 
cells are the active agents in secreting, the basement membrane furnishes a 
support for the cells, the capillaries bring a supply of blood near the cells, 
while the nerve fibres connect the cells with the nervous system which con¬ 
trols their activity. 

The simplest arrangement of these parts is where the gland cells are 
spread over a smooth surface as shown in Fig. 1. Such an arrangement is 
called a secreting surface. It is employed where on’y a small amount of 
liquid is needed and there is a large am unit of surface to furnish it. Name 
such a place. It cannot be employed where a large amount of liquid is 
needed. Fig. 2 shows a plan for increasing the secreting surface, by placing 
the gland cells in a tube, or sac shap :d cavity. These are known as simple 
tubular or simple sacular glands according to the shape of the cavity. Fig. 
3 shows how the secreting surface is still further increased by dividing the 
tubes and sacs into parts. In some cases the tubes and sacs branch and 
divide until a large mass, such as the liver or pancreas, is formed. It is then 
called a compound gland. It contains the same elements as the simple 
gland and only differs from it in the greater number of its branches. S' e 
Fig. 4. The compound glands are situated a small distance from the al - 
mentary canal and the liquid they secrete is transferred to it by small tubes 
called ducts. (Copy drawings to show the different kinds of glands.) 

The Digestive Glands are situated along the alimentary canal and into 
it they discharge their liquids. Within the canal the liquids come in 
direct contact with, and act upon, the food. Information concerning the lo¬ 
cation, structure, and secretions of these glands is easily obtained from the 
usual texts on Physiology. 

Salivary Glands. Locate and describe the different kinds. Are they 
simple or compound? IIow do they differ in size? Which are affect¬ 
ed by the mumps? When are they most active? How much saliva is 
secreted daily by them? Locate the ducts which convey the saliva to the 
mouth. 









































48 


Gastric Glands. Where located? Number? Size? How much liquid 
do they secrete daily? What is it called? To what class of glands do they 
belong? 

Liver. Give its location, size, color, and general structure. How much 
bile is secreted daily? The liver, unlike the other glands, is m ire or les3 
active at all times and for this reason has a reservoir called the gall bladder 
which retains the bile until it is needed for digestive purposes In addition 
to assisting in digestion the liver removes certain impurities from the 
blood, and forms, from the materials which come to it through the portal 
vein, a sweetish substance called glycogen. “This is formed during di¬ 
gestion and is stored in the liver, to be gradually transformed, in the inter¬ 
vals of digestion, into grape sugar.” In this way the liver stores the di¬ 
gested material until it is needed by the system. 

Pancreas. Give its location, size, shape, and general structure. What 
is its secretion called? How much of this liquid is daily secreted? 
Where do the ducts from the liver and pancreas enter the intestine? 

Intestinal Glands. These are embedded in the mucous membrane of 
both the small and large intestines and are, for the most part, simple tubular 
glands. What is their secretion called? How much is there of it? 

How much liquid is secreted daily by all the digestive glands? How 
does this compare with the total amount of food consumed? What becomes 
of the excess of the liquids? 

Digestive Processes .— 

The different processes through which the food pisses, in oemg reduced 
to the liquid state, are mastication, insalivation, deglutition , stomach 
digestion, and intestinal digestion. 

Mastication. Of what does this process consist? By whatorgans is It 
accomplished? Why should it be performed slowly and thoroughly? One 

purpose of mastication is illustrated by the following 

Experiment. Pulverize a teaspounful of salt and place it in one of two tumolers. 
In the other, place the s ime amount <>f coarse salt. Add water until each tumbler is half full 
and observe in which the salt first dissolves. In which does the water come in contact with 
the greater surface of salt? 

Since mastication helps reduce the rood to a proper condition for swal¬ 
lowing and for the rapid action of tb t digestive fluids, it is to he regarded 
as a preparatory process. 

insalivation. This process consists in the mixing of the food with the 
saliva. How does it prepare the food for swallowing? How does it enable 
us to taste substances? Name two substances which are dissolved by the 
saliva. It acts on starch, changing it into grape sugar. What is the ad¬ 
vantage of such a change? This action, however, is only temporary, as it 
is checked in the stomach by the acid of the gastric juice. The active agent 
in saliva is ptyoline. 


























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Deglutition, or swallowing - , is the process by which food is transferred 
from the mouth to the stomach. How is it transferred from the mouth to 
the pharynx? From the pharynx to the stomach? Locate the muscles 
which do this work. How much of the swallowing process is voluntary? 

Stomach Digestion is accomplished by the gastric juice. The most 
important active agents in this liquid are hydrochloric acid and pepsin. 
These act upon the insoluble nitrogenous food substances, called proteids, 
and change them into soluble substances called peptones. Why is this an 
important change? Good examples of nitrogenous food substances are the 
albumen of lean meat or the white of an egg, the casein of cheese, and the 
legumen of beans and peas. Fatty substances and starch are not digested 
in the stomach. At the beginning of stomach digestion, the muscle at the 
pyloric orifice is contracted, but as digestion proceeds it relaxes at intervals 
to let material pass into the small intestine. How is the food in the stomach 
mixed with the gastric juice? Stomach digestion may be illustrated by 
the following 

Experiment. Prepare artificial g-astric juice as follows: To a half tumblerful of 
water add 15or 20 drops of hydrochloric acid. In this dissolve twice as much pepsin as will 
stay on the point of an average sized knife blade. (Both the pepsin and the acid are obtained 
from the drug store.) Place in the mixture the white of a hard-boiled egg, broken into 
very small pieces. Allow the whole to stand for 24 hours In a place where the temperature is 
about 93 deg.E. During this time portions of the egg will be dissolved. 

Intestinal Digestion i s accomplished mainly by the action of the bile 
and pancreatic juice. The bile has only a feeble action upon any of the 
food substances, but it helps along digestion, indirectly, in different ways. 
1. It counteracts the acid of the stomach, giving the food an alkaline re¬ 
action which is necessary for the action of the pancreatic juice. 2. It in¬ 
creases the peristaltic action of the intestines by acting as a stimulus to 
the muscular coat. 3. It retards the decomposition of food in the intes¬ 
tines. 4. It furnishes a large bulk of liquid which serves to move the 
contents of the intestines readily along. What other functions has the 
liver than that of assisting in digestion? 

The Pancreatic Juice is the most important of the digestive fluids and 
acts with vigor on all classes of foods. 1. It changes starch into grape 
sugar, completing the work begun by the saliva. 2. It changes proteids 
into peptones, finishing the work of the stomach. 8. It emulsifies the 
fats; that is, it breaks them up into very fine particles so that they can be 
absorbed. It also changes a portion of the fats into two soluble substances 
called glycerine and the fatty acids. 

Experiment. To a little sweet, oil in a test tube or small bottle add water and attempt 
to mix by shaking. Result. Then add a liitie baking soda and shake again. The oil is 
broken into very fine particles, forming what may be called an emulsion. 

Health Suggestions. Different physiologists have suggested the fol¬ 
lowing rules with reference to the health of the digestive organs. Think 







52 


about them carefully and And some reason either for obeying or disobeying 
each one: 1. Eat slowly and masticate the food thoroughly. 2. Avoid eat¬ 
ing between meals. 3. Avoid use of all stimulants, such as alcoholic 
drinks, tea, and coffee. 4. Take active exercise daily, in the open air. 

5. Drink little water during meals, but plenty of water between meals. 

6. Impure water should be boiled before drinking. 7. Eat only whole¬ 
some, well-cooked food. 8. Never swallow anything which is not thorough¬ 
ly masticated. 9. Obey your appetite and do not think too much about 
what you eat and how you eat it. 

Care of the Bowels. The undigested contents of the alimentary canal should be reg¬ 
ularly discharged. When this is neglected a condition known as constipation or costivoness 
ensues. This is not only a source of great annoyance but is injurious to the health. In 
most instances it can be avoided by observing the following habits: 1. Have a regu'ar 
time each day for evacuating the bowels. 2. Drink plenty of water between meals. 3. Eat 
generously of fruit and such coarse foods as oatmeal, corn bread, etc. Obstinate cases have 
been cured by simply eating a few mouthfuls of wheat bran each dav. 4. Practice such ex¬ 
ercises as bring the abdominal muscles into play and knead the abdomen with the hands. 

Do not rely upon patent medicines, pills, etc., as they usually leave the canal in a weak¬ 
ened condition. Wheu necessary consult a phjsician. 

References: 

Review Questions. 1 . What is the purpose of digestion? 2. What 
kind of a process is it? 3. How do foods differ with reference to digesti¬ 
bility? 4. What are the three kinds of digestive organs? 5. Name the 
parts of the alimentary canal in their order. Describe its coats. 6. What 
different appearances does the mucous membrane present in different parts 
of the canal? 7. Describe the work of muscles in digestion. 8. Make 
a drawing of a tooth which will show the position of the materials which 
compose it. 9. Describe the tongue and name its uses. 10. Name the 
parts of a simple gland and give use of each part. 11. Show some of the 
plans for increasing the surface for secreting cells. 12. What is the prin¬ 
cipal constituent of all digestive fluids? 13. Give the different functions 
of the liver. 14. Why is the liver the only gland with a reservoir for its 
fluid? 15. Where, by what fluids, and in what manner are fat meat, the 
white of an egg, the starch of a potato, salt, and sugar digested? 


-: o :- 

Absorption. 

In general, absorption means the penetration of a liquid into the small 
spaces in the body of a solid. Applied to physiology, the term refers to the 
entiance of liquid materials into the blood vessels. The great source of 
liquid materials for the blood is the alimentary canal, and the study of 
absorption will therefore be confined to it. 











































































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54 


To get from the canal into the blood vessel^ the liquid materials must, 
in all instances, pass though membranous walls. This passage takes place 
according to the principle of osmosis. The liquid in the blood vessels, 
being denser than that in the alimentary canal, the greater flow is toward 
the blood■ Within the walls of the canal are great numbers of capillaries and 
lymphatic vessels which receive the absorbed liquid materials. 

The Capillaries throughout the entire length of the canal take in 
liquids, but the greater amount of their absorbing is done at the stomach 
and small intestines. The capillaries absorb all kinds of liquid material 
except the emulsified fats. 

The Lymphatic Vessels are also capable of absorbing, to a small extent, 
from all parts of the canal, but all of their important work of this kind is 
confined to the small intestine. Here they have a remarkable development, 
forming a system of tubes peculiar to themselves, called 

The Lacteals. The lacteals are special absorbent vessels for the emul¬ 
sified fats. They have their beginnings in the small elevhtions of the 
mucous membrane of the small intestine, called the villi. (Copy drawing.) 
The different tubes comprising the lacteals run together, to form larger and 
larger ones in the mesentery, until they reach the thoracic duct. Wlii e 
they have for their principal function the absortion of fats, they also, 
to a small extent, absorb other substances. 

Two Routes. There are two distinct routes from the alimentary canal 
to the general circulation. If substances are absorbed by the blood vessels 
they pass through the portal vein to the liver. From there they go through 
the hepatic vein to the vena cava ascending, and then to the right 
auricle. If they are absorbed by the lacteals they pass to the thoracic duct 
and through it to the left subclavian vein, then into the vena cava de¬ 
scending, and into the right auricle. (Copy drawing showing these routes.) 

Probi.km: Trace the digestion, absorption, and Anal entrance of lean meat, butter, 
starch, water, salt, and sugar Into the general circulation. 

References: 


General Questions. 1 . Give general meaning of the term absorption. 
What is its special meaning in physiology? 2. Why is the greater flow of 
liquids from the alimentary canal into the blood vessels and not the other 
way? 3. What materials are absorbed by the blood vessels? What by the 
lacteals? 4. What kind of absorbing vessels receive liquid materials from 
the stomach? What kinds from the small intestines? 5. What route 
is taken by the emulsified fat as it goes from the small intestines into the 
general circulation? What by the other materials? 












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Foods. 


The different classes of foods are shown by the following table: 

f Albumen 


Casein 


Organic -j 


Foods 1 


Proteids, or 

’ , , i Mitsui u 

nitrogenous substances-j Q] uten 

[ Legumen 
c Oils and fats 

Non-nitrogenous substances ] Starch 


Water 


Sugar 


Inorganic < 1 Common salt 

( Salts 1 Phosphate of lime 
( Carbonate of lime 

Organic foods are those which have been formed in the bodies of animals 
and plants. The inorganic are furnished by the mineral kingdom. 
Nitrogenous substances are composed of carbon, hydrogen, oxygen, and ni¬ 
trogen. The non-nitrogenous of carbon, hydrogen, and oxygen. Albumen 
is found in abundance in lean meat and in the white of eggs. Casein is 
found in milk and cheese. The sticky part of grain is gluten. Peas and beans 
are rich in legumen Name a food wh : eh contains fat. What foods contain 
oil? Name three foods rich in starch. Name three sugar producing plants. 


Purposes of Food. Food serves two distinct purposes in the body. 1. 
It provides material for the growth and repair of tissues. 2. It furnishes 
heat and force for the body. (Review topic on the growth of cells, page 5.) 

Nearly all the tissues of the body contain nitrogen and therefore re¬ 
quire nitrogenous food for their growth and repair. Animals fed on non- 
nitrogenous substances alone will starve. On the other hand the non-nitrog¬ 
enous foods unite more readily wilh oxygen, and produce fewer impurities 
when they do unite, than the nitrogenous. For these reasons they are es¬ 
pecially adapted to supplying heat and force, 

The demand of the body for heat and force material, exceeds its demand 
for tissue material ordinarily by about “three to one.” The nitrogenous 
and non-nitrogenous foods should therefore be eaten in about that propor¬ 
tion. Should this proportion ever vary? 

Water cannot be classed as a true food, for it undergoes no change in 
thebodv. Yet it is probably the most important substance taken into 
the system. It is present in all tissues, and forms about two-thirds of the 
total weight of the body. A man weighing 150 pounds, if completely dried, 
would lose how much? 

The main uses of water are: 1. To dissolve substances, so 
that they, as liquids, may move from place to place in the body. 
2. To serve as a means of transfer of substances according to the principal 
of osmosis. It accomplishes this purpose by passing through membranes 









m 58 

and cell walls and carrying with it whatever it holds in solution. 3. It 
assists in the discharge of impurities from the body through the lungs, skin, 
and kidneys 4. It assists in the discharge of waste materials from the 
alimentary canal by keeping them in a soft condition. 

The Salts serve various purposes in the body. Some added to water 
increase its dissolving power and are of use in the digestive fluids. Others 
become parts of tissues. Phosphate of lime is a constituent of both osseous 
and nervous tissue. The functions of others are unknown. Many have no 
function in the body and some even, are injurious. 

References: 

Questions, l. Name an example of each of the different kindsof foods. 
2. How do the organic foods differ in origin from the inorganic? 3. How 
do the nitrogenous foods differ in composition from the non-nitrogenous? 
4. What two purposes are served in the body by foods? 5. Why are 
the nitrogenous foods sometimes called the “tissue builders?” 6. What 
must the food do in the cells in order to liberate heat and force? 7. Why 
are the non-nitrogenous food better adapted to supplying heat and force than 
the nitrogenous? 8. Account for the fact that people in cold climates eat large 
quantities of fat. 9. What is wrong with a bill of fare consisting of eggs, 
lean meat, beans, and rye bread? Suggest a better one. 

——-: o :•- 

Excretion. 

As a result of the chemical changes which take place in the cells, waste 
materials are constantly being formed. The waste materials which result 
from the uniting of oxygen with fatty, sugary, and starchy substances, are 
carbon dioxid and water. Those formed by the union of oxygen with 
nitrogenous substances are carbon dioxid, water, and urea. It is thus seen 
that there are only three waste materials formed in large quantities. Of 
these urea is the only one containing nitrogen. Only a small amount of the 
water discharged from the body is formed there. Its discharge in such 
large quantities is necessary to the removal of the other impurities. In ad¬ 
dition to the waste substances already named there are quite a number, such 
as salts of different kinds, which are formed in small quantities. 

From the cells, where they are formed, the waste materials (ind their 
way into the*blood from which they are removed by the Organs of Excre¬ 
tion. Xhese, named in the order of their importance, are the kidneys, 
lungs, skin, and liver. 

The kidneys are two, bean shaped organs siluated in the back and 
upper portion of the abdominal cavity, one on eich side of the spinal 






























































































Oft 60 

column. They weigh from 4 to 6 ounces each and lie between the 
abdominal wall and the peritoneum. Two large arteries from the aorta, 
called the renal arteries , supply them with blood, while they are connected 
with the vena cava ascending by the renal veins. They remove from the 
blood an exceedingly complex liquid called the urine, the principal constitu¬ 
ents of which are water, salts of different kinds, and urea. The kidneys 
pass their secretion to the bladder by two slender tubes, called the ureters. 
(Copy Drawing.) 

Minute Structure of the Kidneys. The inner substance of each kidney 
contains a great number of small tubes, called the uriniferous tubes , which 
penetrate it in all directions. Each of these tubes has its beginning in a 
cluster cf fine capillaries which is surrounded by a membranous sheath, 
called th e capsule. (Copy drawing.) 

From the capsule each tube extends toward the hollow cavity on the 
inner side of the kidney, called the pelvis of the kidney. But before reach¬ 
ing that place it makes several turns upon itself and joins other tubes. A 
layer of secreting epithelial cells line the tubes and they are surrounded on 


the outside by a network of capillaries. 

The Work of the Kidneys is divided between the clusters of capillaries , 


at the beginning of the tubes, and the secreting cells lining them. The 
former separate water and Lh q salts dissolved in it, from the blood, while 
the latter separate the urea. 

Pit,»ni em: Trace urea, water, and mils from the place where they are separated from 

the blood, through the different tubes, till they reach the bladder. 

The Lungs have already been studied. They are the principal organs 
for removing carbon dioxid. They also remove small quantities of water 
and “animal matter.” It is the last named impurity that gives air in poorly 
ventilated rooms its peculiar odor. IIow prove the presence ot carbon 
dioxid in the breath? How show the presence of watery vapor? 

Problem: Trace carbon dioxid from the place where it is separated from the blood, 
through the different air passages, till it gets outside of the body. 

The Skin is an organ with many functions and it will be more fully de¬ 
scribed at another place. Its excretory product is the perspiration or sweat 
which consists of water with a small amount of urea, common salt, and 
other substances dissolved in it. It is separated from the blood by the 
sweat glands. Find a description of these in some physiology. The per¬ 
spiration comes from the skin either as a liquid or in the form of an invisi¬ 
ble vapor. When a liquid it is called sensible perspiration; when a vapor, 


i licit; I ley IULts • , . 

Experiment Lay the palm of the hand against a cold window pane tor a short time. 
Account- for the collection of moisture on the pane. Does this experiment illustrate sensible 
or insensible perspiration? 

The work of the skin is quite similar to that of the kidneys. In reality 
it does on a small scale what the kidneys do on a large scale. When the 
kidneys are diseased the skin becomes more active. Why should it? Why 
should one bathe frequently? 








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The Liver dischatges its impurities in the hile. This liquid has not 
been studied sufficiently to determine what portions of it are excrement itious 
and what portions assist in digestion. 

References: 


Review Questions, l. How are impurities produced in the cells? 
2. Name the organs of excretion in the order of their importance. What 
ones have otter functions? 3. How do the impurities get from the cells to 
the organs ot excretion? 4. Make a sketch of the kidneys, showing their 
connection with the large blood vessels and the bladder, naming parts. 
5. In what do the uriniferous tubes have their beginning? In what do 
they terminate? With what are they lined? 6. Bright’s disease of the 
kidneys affects the uriniferous tubes and interferes with their work. What 
impurity is then left in the blood? 7 . What impurities are removed by the 
lungs? What by the skin? 


-: o :- 

General Summary. 

We have seen that the body is an aggregation of different kinds of cells; 
that it grows by the growth and reproduction of these cells; and that the 
life of the body, as a whole, is maintained by keeping these cells alive. We 
have also seen that the work of the systems, so far studied, is to take care 
of the different cells of the body. This they do by preparing, circulating, 
charging with oxygen, and keeping pure, a liquid (the blood) which supplies 
them with material necessary for their work, growth, and the carrying on of 
their vital processes. Answer carefully the following questions: 

1. What purpose does oxygen serve in the cells? 2. How does it get 
from the atmosphere to the cells? 3. What different purposes does ihe 
liquid food serve in the cells? 4. IIow is the liquid food prepared? 5. How does 
it reach the cells? 6. What is the purpose of the blood? 7. Why must it 
circulate? 8. Name the principal waste materials formed in the cells. 9. 
Trace each from the cells to the excretory organs, and through them, to the 
outside of the body. 

Problems: 1. Trace starch, fat, and albun.cn entirely 1hrough the body, telling-what, 
changes they undergo indigestion, by what routes they reach the general circulation, what 
purposes they serve in the ceils, what impurities they form, and finally, how these impurities 
are removed from the body. 

2. Write a sketch, of 200 words or less, setting forth the plan of maintaining life in the 
body. 


















































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Dissectional Review. 

For this work the body of a cat is well adapted and usually obtainable. These directions 
therefore refer to the cat, though they may be applied to other small animals, such as the rab¬ 
bit, squirrel, or rat. 

The cat may be killed with chloroform in the following'manner: Warm a small, tight 
box, having a close-fitting lid, by placing it near a stove or fire-place. Put the cat in the box 
and place on the lid, but leave a small opening, through which pour 3 or 4 tab'espoonfuls of 
chloroform. Then close the opening and fasten down thitid. In about 1,’ minutes the cat 
will be dead. 

Before the cat stiffens stretch it on a board by laying it on its back and driving a nail 
through each foot. The head should be drawn up and a tack driven through each ear into the 
board, to prevent the specimen's sagging in the center. Stand the board on end, in a slanting 
position, by a prop railed at the back. This much of the work should be done an hour or so 
before the dissection is to begin. The teacher should also make a preliminary examination 
of the abdomen to see that it is in a fit condition for class study. 

The following materials will be needed during the dissection and should be near at hand: 
A sharp knife with a good point, a pair of heavy scissors, a vessel of water, some cotton bat¬ 
ting or a sponge, a bent glass tube for inflating the lungs, some fine cord, a few tacks, and a 
hammer. 

During dissection, the specimen should be kept as clean as possible. The escaping 
blood should be mopped up with cotton or a damp sponge. Care must be taken not to cut into 
the stomach or intestines before the class. The leacher should make at least one dissection pri¬ 
vately before attempting a class demonstration. The best results will be obtained by observ¬ 
ing the order of work given below. 

1. Cut through the abdominal wall in the center of the triangular space where the ribs 
converge. From hei e cut a slit downwa d to the lower portion of the abdomen and sideward, 
each way, as far as convenient. Tack the loosened abdominal walls to the board and proceed 
to study the exposed parts. Observe the muse es in the abdominal walls and the fold of the 
peritonhum w hich forms an apron-iike covering over the intestines. Remove and study the 
liver. Note its color, shape, size, lobes, and reservoir foi the bile. Find the stomach, pan¬ 
creas, spleen, and parts of the intestines. Observe I heir position and connections. 

2. Tie the canal lightly in two places, half an inch apart above the stomach and cut it 
in two between these places. Likewise tie and cut the rectum. The stomach and intestines 
may now be removed from the abdominal cavity and studied to better advantage. Observe 
tlie position, shape, and attachment of the pancreas. Examine the mesentery and its con¬ 
nections with the intestines. Notice the divisions of the portal vein and the lacteals 
parsing through it. fear the stomach and intestines lrom the mesen'ery and measure their 
length. 

3. Examine the kidneys and their connections. Observe that they lie back of the per¬ 
itoneum. Find the tidies, the ureters, which connect them to the bladder and renal artery 
and vein whicli connect each one to the aorta and vena cava ascending. 

4. The thorax may now be. studied. Begin at the throat and slit the skin down to the 
abdomen. Then tear and cut it back to the shoulders. Examine the intercostal muscles, 
between the ribs, and the diaphkaom, below the thorax. 

5. Cut into the throat until the trachea is reached. Pull it out, cut it loose at the up¬ 
per end. and insert a tube through which air may be blown into the lungs. Inflate the lungs, 
observing that the diaphragm m tves downward while the 'ibs move outward and upward. 

6. With a pair of scissors cut away one side of rhe t horax without injuringthe diaphragm 
or lungs. Find a vertical, meinbrtnous partition, separating the thorax into two parts. This 
forms a part of the pleura. Inflate the lungs, a second time, to see lio»v coinplete y they 
fill out the thoracic cavity. 

7. Cut away the remaining ribs and remove the lungs, windpipe, heart, and 1 irge blood 
vessels attached together. Infia'elhe lungs again, observing that they retain the shape of the 
thorax and completely surround the heart. Find the aorta and test its elasticity. 

8. Dissect the skin from around one side of the mouth and examine the salivary 
glands. Cut the attachments of the lower jaw on one sidu and press it down, so as to show 
1 he contents of tlie mouth and its connection with the pharynx. 




The Osseous System. 

The skeleton or frame work of the body is composed chiefly of osseous, 
cartilagenous, and connective tissues. What are the properties of each of 
these tissues? They are all concerned in the formation of the parts of the 
skeleton, known as the bones. 

Observation. Study one of the long bones of the body of an animal, such as the le¬ 
mur. Test Its hardness, strength, and stiffness. Saw it in two a third of the distance from 
one end and saw the short piece in two lengthwise. Compare the structure at different 
places. Find rough elevations on the outside for the attachment of muscles and small open¬ 
ings into the bone for the entrance of blood vessels and nerves. 

Minute structure of Bones. The hardness and stiffness of bones is 
given them by the hone cells. Bone cells differ from the other cells of the 
body in having very thick and hard cell walls which are composed princi¬ 
pally of carbonate and phosphate of lime. These substances form what is 
known as the “mineral matter” of the bones. The bone cells are collected 
into small groups which are found in irregular shaped cavities called the 
lecunae. The toughness of the bone is caused by the presence of a large 
amount of “animal matter,” principally connective tissue, which is mixed in 
with the bone cells. The proportion of the animal to the mineral matter 
of the bone is about two parts of the former to one of the latter. 

Experiments. 1. Soak a slender bone, like that in the leg of a chicken, over night in a 
mixture of one part of hydrochloric acid with four parts of water. The acid dissolves out the 
mineral matter. Ascertain by bending, stretching, and twisting.what properties the bone has 
lost. What therefoieare the properties given bone by the mineral matter? 

2. Burn a small piece of bone in a clear gas flame or on a bed of coals until it ceases to 
blaze. Burning destroys the animal matter. By testing find what properties the bone lias 
lost, What then are the properties given bone by the animal matter? 

How Bone Cells are Nourished. They, like the other cells of the body, 
receive their nourishment from the blood. The blood reaches those within 
the bone through a great number of small canals which penetrate it 
in all directions. The largest of these are called the Haversian canals. 
(Named from Havers who discovered them.) Branching off from these, at 
right angles, are many smaller canals, called the canaliculi. These pene¬ 
trate to the lecunae where the bone cells are found. (Copy drawing repre¬ 
senting these canals.) 

The cells at the surface of the bone get their nourishment from the 
blood vessels in the membrane surrounding the bone. What is it called? 

Gross Structure of Bones. The gross structure of bones is best shown 
by a study of a single bone such as the femur. 'The two ends of this bone are 
capped by a layer of elastic cartilage while its entire surface is covered by a 
sheath of connective tissue, called the periosteum. In the central part is a 
long hollow portion, called the marrow cavity. This is lined with an inner 
sheath, the endosteum, and is Ailed with a fatty substance called the yellow 
marroiv. Around the marrow cavity the bone is very dense and compact. 
At the ends the bone substance is coarse and spongy, containing a great 







68 

number of small cavities which are filled with the red marrow. What is 
the supposed function of the red marrow? (Copy drawing and name parts.) 

Plan of the Skeleton. The central portion of the skeleton consists of 
the head and a faily rigid bony axis, called the spinal columm.. To the 
spinal column, all the other portions of the skeleton are either directly or 
indirectly attached. The ribs are directly attached, forming a framework 
for the breathing organs. Attached indirectly by two bony arches, the 
pelvic and shoulder girdles, are the two portions of the appendicular skele¬ 
ton. To the shuulder girdle are attached the upper extremities, while the 
lower extremities are attached to the pelvic girdle. (Illustrate the plan of 
the skeleton by a drawing.) 

The Names of the Principal Bones and their grouping in the body are 

shown by the following table: 



Axial Skeleton. 


II. 

Appendicular Skeleton. 



Skull, 28. 


A. 

Shoulder Girdle, 4. 


1. 

Cranium, 8. 


1. 

Clavicle, collar bone. 

2 


a. Frontal, forehead. 

. 1 

2. 

Scapula, shoulder blade. 



b. Parietal. 

.2 

B. 

Upper Extremities, 60. 



c. Temporals, temples. 

2 

1. 

Humerus. 

. .2 


d. Occipital. 

.i 

2. 

Radius... 

. . 2 


e. Sphenoid . 

.i 

3. 

Ulna. 

. .2 


f. Ethmoid.. 

i 

4. 

Carpals, wrist bones. 

16 

2. 

Face, 14. 


5. 

Metacarpals. 

10 


a. Inferior Maxillary. 

. i 

6. 

Phalanges. 

28 


b. Superior Maxillaries. 

2 

C. 

Pelvic Girdle, 2. 



c. Palatine, palate. 

.2 

1. 

Os innominatum. 

2 


d. Nasal bones. 


D. 

Lower Extremities, 60. 



e. Vomer. 

.1 

1. 

Femur, thigh bone. 

.2 


f. Inferior Turbinated. 

2 

2. 

Tibia. 

.2 


g. Lachrymals. 

2 

3. 

Fibula. 

.2 


h. Malars, cheek bones. 

2 

4. 

Patella, kuee cap. 

2 

3. 

Bones of the Ear, 6. 


5. 

Tarsals, ankle bones . 

14 


a. Malleus. 

.2 

6. 

Metatarsals, bones of the in 



b. Incus . 

2 


step. 

10 


c. Stapes . 

2 

i • 

Phalanges, bones of the toes. 

28 


Spinal Column, 20. 





1. 

Cervical, or neck vertebras. . . 

. .7 

Study the skeleton until you are, 

at 

2. 

Dorsal, or thoracic vertebrae. 

12 

least, able to locate and understand 

3. 

. Lumbar vertebrae . 

.. 5 

the uses of all the bones given in this 

4 

. Sacrum . 

. . 1 




5 

. Coccyx . 

.1 





C. Thorax, 25. 







































Size ancl Shape of Bones. The bones vary in shape and size to suit 
their position and use in the body. Some bones, like the humerus, are 
adapted to giving form, strength, and stiffness to parts of the body. Others, 
like the pelvic bones, are fitted for supporting and protecting. Others still, 
as the wrist and ear bones, are adapted, by their size and shape, to giving a 
peculiar kind of motion. Where is the smallest bone in the body? Where 
is the largest? Why should the skull bones and the ribs be flat? Why 
should the femur, and the humerus, be long and cylindrical? Why should 
the bones of the wrist be short and rounded? 

The Bones as Instruments of Motion. The most important use of the 
bones is to serve as levers in the production of motion. A lever may be de¬ 
scribed as a stiff bar which is used in lifting weights. It is made to turn on 
a fixed point of support called the fulcrum. The force applied to the bar 
is called the power and that which is lifted is termed the weight. Levers 
are of three kinds, known as the first class, second class, and third class. 
The only difference between them is in the position of the power,weight, 
and fulcrum. In the first class the fulcrum is between the power and 
weight. In the second class the weight is between the fulcrum and the 
power. In the third class the poiver is between the fulcrum and weight. 
(Make drawings to illustrate the different kinds of levers.) 

In the body the muscles furnish the power, a part of the body itself, or 
some object to be lifted, serves for the weight, and the fulcrum is generally 
at a joint. While all the different classes of levers are represented in the body, 
the majority of them belong to the third class. The special advantage of 
this class is that the power by moving a short distance can move the weight 
a long distance- The contraction of the longest muscles does not amount 
to more than two or three inches, yet they are able, by this form of lever, 
to make portions of the body move as many feet. Furnish illustrations of 
this fact. Find a representative of each of the three classes of levers, in 
the body. 

Articulations. 

Any place in the body where two or more bones are joined together is 
called an articulation. Articulations are of two kinds, known as the 
movable and the immovable. A great number of the latter are to be found 
ia the skull where projections from one bone interlock with those of an 
other, the tissue between beiHg very thin. This kind of an articulation is 
called a suture. (Examine bones of a skull.) 

A Joint is a movable articulation. It must be so constructed that the 
bones glide over each other easily and without friction. The parts of 
the bones which help to form joints, are smooth and are covered with a 
thick layer of cartilagenous tissue. This serves as an elastic cushion to 
deaden shocks. The cartilage is covered with the synovial membrane, the 
inner surface of which secretes the synovial fluid. What is the purpose of 























































this fluid? It is retained in the joint by the synovial membrane which 
surrounds the ends of the hones and extends from one to the other so as to 
form a closed sac. Is this a serous or a mucous membrane? Why? Strong 
bands of connective tissue, called ligaments join the boues together. Are 
these elastic or inelastic? Why should they be? The fibres of the liga¬ 
ments are interwoven with the periosteum, making a very secure attachment. 
In some cases the ligaments form one continuous sheath around the joint, 
making what is called a capsular ligament. Furnish an example. (Make 
a drawing to show the parts of a joint. Practice on this until it tan be 
made from memory.) 

The Different Kinds of Joints are th eballand socket, the hinge, the pivot, 
and th e combination joint. The ball and socket joint consists of a ball shaped 
end of bone which fits into a cup-shaped cavity, called a socket. Name ex¬ 
amples. This joint admits of motion in what directions? In the hinge 
joint the bones are grooved and fit together something after the plan of a 
hinge. Name examples. Of what motion is it capable? The pivot joint 
is formed by one bone rotating or turning against another. lutnish ex¬ 
amples. This joint admits of motion around a given axis. Where a joint 
combines the motion and structure of some of the above joints it may be 
called a combination joint. Furnish examples. 

Questions on Hygiene. What is the danger of having children walk 
at too early an age? Why should children not sit on seats too high for their 
feet to reach the floor? Why is moderate exercise beneficial, and violent 
exercise injurious to the bones? How is a broken bone ‘‘set? What is a 
sprain? What is a dislocation? Why must a sprain have careful treat¬ 
ment? 

References: 


Review Questions, i. Of what three kinds of tissue is the skeleton 
composed? 2. Name and locate 1 he bones of the cranium. 3. Name and 
locate those of the face. 4. Of what use are the ribs? 5. To what is the 
hardness of the bones due? 6. To what is their toughness due? 7. Plow 
separate the animal matter of a bone from the mineral matter? 8. How re¬ 
move the mineral matter? 9. How does the blood penetrate to the bone 
cells within the bone? 10. Describe the gross structure of a bone. Illustrate 
with a drawing. 11. What is a lever? Describe the three different kinds. 
Name an example of each in the body. 12. What peculiar advantage has a lever 
of the third class? 13. In levers of this class will the force of the muscular 
contraction be greater or less than the weight of the substance lifted? 14. 
Name the parts of .a joint and give the use of each part. 15. How is the 
synovial fluid kept in the joint? 16. How are the ligaments attached to 
the bones? 
















The Muscular System. 

The muscular is the most abundant of the tissues, forming by weight 
more than one-half of the entire body. What important properties does it 
possess? What is its chief use in the body? Muscular tissue, in order to 
accomplish its purpose, is organized into groups, called muscles. How 
many muscles in the body? 

Muscle Cells are among the largest in the body. They are of two kinds, 
known as the voluntary and the involuntary. Each voluntary cell is 
composed of a long sack—the cell wall—which is filled with muscle pro¬ 
toplasm, the contractile substance of the cell. The surface of this cell 
shows a great number of very fine lines, on account of which it is 
said to be striated or striped. Many are found connected with the ends 
of nerve fibres. Involuntary cells differ from the voluntary,in being spindle 
shaped and in having a smooth, instead of a striped, surface. It also has 
a well defined nucleus. (Copy drawing showing the two kinds of cells.) 

Two Kinds of Muscles, known as the voluntary and involuntary, are 
built up from the two kinds of muscle cells. The voluntary muscles, which 
form the larger and more important class, are built up from voluntary cells. 
A study of the structure of these muscles shows the cells to be placed end 
to end, forming fine muscle threads or fibres. A number of these threads 
form a slender bundle, around which is placed a thin layer of connective 
tissue. These bundles are again bound into larger ones by bands of connect¬ 
ive tissue, so that the entire muscle consists of bundles of bundles of muscular 
threads. The whole is surrounded by a single sheath of connective tissue, 
called the perimysium- At the ends the muscles are attached to tendons 
which connect them with the bones. The involuntary muscles are built up 
from involuntary cells. These are not arranged into bundles, but are inter¬ 
woven with each other to form thin bands or sheets. 

Observation. As an example of a voluntary muscle examine one, such as is found in 
the leg of a cal , rabbit, or chicken. Note color, shape, and outside covering. Observe how 
the perimysium grades into the tendon. Observe the properties of the tendon and trace it to 
the bone with which it is connected. 

As an example of an involuntary muscle, examine the muscular coat of the stomach of a 
beef. A section may be cut out, washed, and prepared for class study. Compare its color, 
shape, covering, etc., with that of the voluntary muscle. 

Differences Between Voluntary and Involuntary Muscles. 1 . The vol¬ 
untary muscles are under the control of the will; the involuntary are not. 

2. Voluntary muscles arc reddish in color, while the involuntary are light 
and pale. There are exceptions to this, the most notable being the heart. 

3. The voluntary are usually attached to bones which they move as levers; 
the involuntary form bands around hollow cavities and tubes, such as the 
stomach and arteries. 4. The voluntary muscles contract and relax 
quickly; the involuntary contract and relax slowly. 

































76 


Muscular Stimuli. The natural condition of a muscle is that of re¬ 
laxation. It is made to contract by the action of something else upon it. 
That which acts upon a muscle to cause it to contract is called a stimulus. 
All the muscles of the body are controlled by the nervous system which 
furnishes a stimulus known as the nervous impulse. This originates in 
nerve centers and reaches the muscles through the nerves. It will receive 
further study in connection with the nervous system. 

There are also other muscular stimuli. The muscles of the leg of a 
frog, recently killed, have been made to contract by touching them with 
luot or cold substances, by passing currents of electricity through them, by 
pricking or pinching them, and by the application oi chemicals, such as 
acids, salts, etc. Heat and cold, electricity, mechanical irritation, and 
certain chemicals are therefore to be classed as muscular stimuli. None of 
these, however, are made use of in the body to cause muscles to contract. 

What Happens When a Muscle Contracts. Careful experiments, upon 
the muscles of frogs, have proved that the following things occur when a 
muscle contracts: 1. The oxygen and certain food substances in t he 

muscle are used up. 2. Waste materials such as carbon dioxid and urea 
are produced. 3. Heat is produced. 

Blood Supply of Muscles. The rapid chemical changes in the muscles 
demand a large supply of blood, which shall furnish liquid food and oxygen 
and remove the waste. Blood vessels penetrate them in all directions and 
the capillaries lie very close to the individual cells. Provision is also made, 
through the nervous system, whereby the flow of blood in a muscle is in¬ 
creased when it is at work. 

Muscular fatigue is supposed to be caused by the waste matter not being 
removed from the muscle as fast as it is formed. 

Attachment to the Bones. The voluntary muscles are attached to the 
bones by tough strips of inelastic connective tissue, called tendons. Why 
should they be inelastic? The tendon is interwoven with the periosteum 
of the bone at one end and the perimysium of the muscle at the other, 
making firm and secure attachments. Name and locate the strongest tendon 
in the body. 

Plan of Placing Muscles. The voluntary muscles are, in most eases, 
placed so as to work in opposition to each other. For example, one muscle 
will be placed so t hat its contraction wiil bend a joint, while another will 
be so placed that its contraction will straighten the same joint. 

Muscles are classed, according to their position and use in the body, as 
follows: Flexors and extensors, adductors and abductors, rotators, radi¬ 
ating and sphincters. These are arranged in pairs. Thcflem>rs and exten- 
•sors form a pair for bending and straightening joints; the adductors and 
abductors , for drawing the limbs toward the axis of the body and moving 
them away: the rotators (two kinds), for twisting and untwisting joints; the 







78 

radiating and sphincters, for opening and closing natural openings. Find 
examples of each of these different classes of muscles. 

Work of the Involuntary Muscles. The motions of the body which are 
directly concerned in maintaining life are brought about by involuntary 
muscles. The most important of these are the contracting of the heart, 
and the motion of the respiratory and digestive organs. Why should such 
important motions be involuntary? 

Effect of Muscular Contraction on the Circulation of the Blood. The 
veins contain many valves. Muscles contracting against the walls of the 
veins, close them up, forcing the blood out of them. The valves will then 
cause the blood to flow which way? As the muscles relax the veins are 
again filled by blood from the capillaries. In this way the muscles help 
force the blood from the capillaries hack to the heart. This work of the 
muscles is considered by many physiologists as very important. How does 
muscular contraction cause the lymph to flow? 

Necessity for Exercise. The hygiene of ihe muscular system may 
all be expressed in the one word “exercise.” The fact that more than half 
the entire body, by weight, is muscular tissue, makes a certain amount of 
daily exercise imperative. If this is neglected the muscles begin a slow 
process of degeneration which results in their becoming weak, soft, and 
flabby. But the worst effects of neglected exercise, are to be observed on 
other portions of the body. The circu ation is diminished in force, the 
blood loses large numbers of its red corpuscles, the breathing capacity is 
lessened, the excretion of waste is retarded, appetite + 'aiIs, power to resist 
disease is diminished, and energy for both mental and physical work is lack¬ 
ing. In brief, the surest and easiest way to become a helpless invalid would 
be to cease from all physical exercise. 

What precautions should be observed in taking exercise? Suggest 
forms of exercise suitable for the “brain woruer.” What kinds of exercise 
develop the lungs? How much should be taken daily? 

References: 

Review Questions, l. Describe a voluntary muscle cell. 2. Show 
how the voluntary muscle is built up. 3. Describe an involuntary cell and 
show how the involuntary muscle is built up. 4. State four differences be¬ 
tween voluntary and involuntary muscles. 5. How is the nervous system 
able to make the muscles contract? 6. Why should a muscle be well sup¬ 
plied with blood? Why should the supply be increased when the muscle 
works? 7. What different things happen in a contracting muscle? 8. 
What is the supposed cause of fatigue? 9. How is the tendon at¬ 
tached to the muscle and the bone? 10. Describe the plan of placing 
muscles with reference to joints. 11. What work of the body is performed 
by involuntary muscles? 12. How does muscular contraction assist in ’he 
circulation of the blood and lymph? 13. What happens to the muscles 
when insufficient exercise is taken? 14. How does a lack of exercise affect 
other portions of the body? 


































































































, 













































































The Skin. 

The skin is the outside covering of the body. It consists of two layers:— 
the dermis, or true skin, and the epidermis, or cuticle. 

The Dermis is the under and thicker foyer of skin and is made up main¬ 
ly of a dense network of connective tissue fibres. This gives to the skin 
its toughness. Interwoven with the connective tissue, are numerous 
small blood vessels, nerves, lymphatics,oil glands, and perspiratory glands. 
State the purpose of the blood vessels. The nerves terminate in small bulb¬ 
shaped organs called touch corpuscles. Their office is to enable us to feel. 
The lymphatics are absorbent vessels. The oil, or sebacious, glands are 
situated by the roots of hairs. What is their purpose? Describe the struct¬ 
ure of the perspiratory glands and give their function. 

At its outer surface, the dermis is exceedingly rough and uneven, form¬ 
ing numerous elevations called the papillae. Each papilla contains the 
loop of a capillary vessel and a nerve fibre, and many of them are crowned 
with touch corpuscles. The inner surface of the dermis is attached to the 
parts beneath by a loose network of connective tissue fibres. (Copy drawing 
showing structure of the skin. Name parts.) 

The Epidermis, or cuticle, is much thinner than the dermis. It is 
tough, non-sensitive, and, in some places, rough and hard. It contains no 
blood vessels, nerves, or lymphatics. Its purpose is purely protective. 

Observation. Examine the cuticle of the hand. Where is it thickest? Account for 
the difference in thickness at different places. Pick a thick portion of it with a pin to see if 
pain is felt. Inference. 

The cuticle grows by tf e multiplication of cells at its under surface, 
they receiving nourishment from blood vessels in the dermis. At this 
place the cells of the cuticle are full and round, while at the outer surface 
they are (lat and scalv. Account for the difference. Wherethe cuticle joins 
the dermis is a layer of pigment, or color, cells which give the color to the 
skin. The hair and nails are modifications of the cuticle. 

A Hair is a long, slender cylinder of epidermis. It grows from a kind 
of pit in the dermis, by the addition of cells to its inner end. Can the cut¬ 
ting of the hair have any effect upon the rapidity of its growth? Give uses 
of the hair. 

The Nail is composed of a number of hard, flat epidermal cells. It 
grows in length by the addition of cells to its root; it grows in thickness by 
the addition of cells to its under surface. Thai part of the dermis from 
which the nail grows is called the matrix. Of what use are the nails? 
How may relief be obtained in ease of a bruise under the naP? 

Observation. Examine a finger nail. Is the front or back portion the ihicker? Ac¬ 
count for the difference. What is a proof that the nails tire not sensitive? 



§2 

Functions of the Skin. a. It serves as a protective covering for the 
body. Which portion is purely protective? b. It purities the blood by 
removing waste matter through the perspiration. By what is this work 
accomplished? c. It is the organ of feeling. What portion of it can feel? 
d. It is able to absorb liquids. What part of it does this? e. It regulates 
the temperature of the body; i. e. it keeps the body from getting too cold or 
too hot. 

How the Skin Regulates Temperature. It assists in keeping the 
body warm by acting as a poor conductor of heat and preventing its escape. 
It serves to cool the body in two ways:—1. By the radiation of heat 
from its surface as from a stove. 2. By the evaporation of the perspiration 

Experiments, l. Wet the back of the hand with water and move it throujili the air io 
hasten evaporation. Observe that as the hand dries, a sensation of co!d is felt. Repeat the 
experiment, using alcohol instead of water and noting difference in eff ect. Alcohol evaporah s 
faster than water. 2. Wrap a thin layer of cotton around the bulb of a thermometer and wet 
the cotton with alcohol. Move through the air to hasten evaporation. Note fall of the 
mercury . 

The above experiments prove the principle that a liquid, in changing to 
a gas, absorbs beat. The perspiration in evaporating, or changing from a 
liquid to a gas, absorbs heat from the body, making it cool. 

The body demands a constant temperature of 98 r F. If the tempera¬ 
ture gets above this the perspiration becomes more abundant and an in¬ 
creased amount of blood is sent to the skin. If it tends to become too cool 
perspiration is lessened and the amount of blood in the skin is diminished. 
The blood supply to the skin is controlled by the nervous system. 

The Hygiene of the Skin j s nearly all included in the problems of keep¬ 
ing it warm and clean. It is kept warm by clothing. Bathing is the 
method of keeping it clean. 

Hygienic clothing should be warm and loose fitting. Why are woolen 
fabrics to be preferred to cotton? Since the clothing next the skin becomes 
charged with impurities, it should be frequently changed. 

• One should bathe often enough to keep the body clean. This will de¬ 
pend upon the season, the occupation of the individual, and the nature and 
amount of the perspiration. As to the kind of hath to be taken and the 
precautions to be observed, no general directions can be given. These must 
he determined by the health and natural vigor of the bather. Care must 
be exercised at all times, however, in preventing too great exposure of the 
body, during the bath. 

References: 

General Questions. i. Give position and relative thickness of the 
dermis and epidermis. 2. Compare them with reference to growth and 
nourishment. 3. Give the function of the different parts of the skin. 4. 

To what is the color of the skin due? 5. How is the color affected by sunlight? 
6. How does the perspiration cool the body? 7. What different kinds of 
epidermis are found on our bodies? What kinds on the body of a chicken? 
8. What precautions should be observed, by one in poor healih, in bathing? 






The Nervous System. 

I. Elements of System. 

Nervous Tissue is of two varieties. These, on account of their color, 
have been designated the “gray matter” and the “white matter.” Both are 
soft, weak, inelastic, and, to the naked eye, appear as structureless 
masses. The microscope, however, she,ws them to be organized into cells 
which have long, thread-like attachments, called fibres. 

The Nerve Cell has the usual parts of a complete cell (name them), 
but differs from all the other cells of the body in having its protoplasm ex¬ 
tended, at one or more places, to form the central part of the nerve fibre. 
The nerve cells, however, in different parts of the body, differ greatly in 
size and shape. (Copy drawing of different kinds of nerve cells.) 

They may exist singly, as in the touch corpuscles of the skin, but are 
usually found ingroups, called the ganglia. What is a single group called? 
The brain and spinal cord are great collections of ganglia. A group of cells 
working together, for the same purpose, forms a nerve center. 

The function of the nerve cell is to produce the nervous force, or energy , 
one form of which passes out through the fibres and is called the nervous 
impulse. 

The Nerve Fibre is a slender filament or thread of nervous matter, leading 
off from the nerve cell and connecting it with some part of the body. Every 
til)re contains acentral part which is a continuation of the protoplasm of 
the nerve cell and is called the axis cylinder. In most fibres the axis 
cylinder is surrounded by two other parts:—-An outside coat, called the 
■primitive sheath , and a middle layer of oily substance, called the medullary 
sheath. (Copy drawing.) 

The function of the (Hires is to transmit, or carry, nervous impulses. 
This work is done wholly by the axis cylinder, the purpose of the other two 
coats being to protect the axis cylinder and to prevent the escape of 
impulses from it. 

The fibres are grouped together forming bundles, called nerves. Locate 
and name the largest nerve in the body. How large is it? About how 
many fibres does it contain? (Copy drawing.) 

Relation of tlie Nerve Cell and Fibre. The nerve cell and fibre are now 
regarded as two parts of the same thing. In their growth, the cell forms 
first and the fibre grows out from it toward that with which it is to make 
connection. The “gray matter” appears to be the true nerve substance, 
being able both' to originate and to transmit nervous energy. In the cells 
it predominates, giving them a grayish color. In most of the fibres the 
“white matter” is in excess, causing them to have a whitish appearance. 
What purpose does it serve? 



' 
























' 




















S6 


The Nervous impulse is the means employed by the nervous system in 
communicating with anrl controlling the different parts of the body. The 
nature of the impulse is not understood,though different theories have been 
advanced regarding it. The best au thorities now look upon it as a sort of wave 
motion which is started in the nerve cell, by chemical action, and which 
travels out, through the protoplasm of the fibres, to the different parts of the 
body. 

Impulses are best known by their effects. They are able both to 
throw muscles, glands, and nerve centers into action, and to check their 
activity. Impulses which throw inactive organs into action, or quicken the 
action of those already at work, are called excitant impulses. Those which 
check altogether, or diminish, the action of working organs are said to be 
inhibitory . 

Connections of Nerve Fibres. One end of every nerve fibre is, of course, 
connected with its own nerve cell The other end will be connected 
with that part of the body into which the cell is to discharge its impulse. 
This may be an involuntary muscle, such as is found in the arteries, heart, 
r digesti ve organs, it may be in one of the many different kinds of glands 
■>r rj rve centers. Then again it may find its way to one of the voluntary 
muscles. The different fibres are named according to their connections and 
the direction and nature of the impulses which they transmit. 

The Different Kinds of Fibres are shown by the following table: 

f . „ . ( Sensory 

Afferent •< -c .. . 

( Excito-motor 

1 Motor i tt, . 

Nerve Fibres -{ Efferent Yaso-motor > < T x .°. ‘ 11 ' 

l Secretory S *■ I " h ' bltH, ' y 
Excitant 
Inhibitory 

Those fibres whose cells are located in special sense organs, at the 
outside of the body, and which convey impulses inward to central ganglia, 
are called afferent fibres. Those whose cells are located within the body 
and which carry impulses outward to muscles and glands are efferent 
fibres. Those which connect different ganglia within the body, are called 
intercentral or commissural fibres. Those afferent fibres whose impulses 
produce sensations (feeling, pain, sight, etc.) are called sensory ; those, 
whose impulses stimulate nerve centers to send out efferent impulses to 
muscles, are called excito-motor. 

Of the efferent fibres, those which go to muscles are called motor , those 
connected with arteries and control the How of blood are Ihe vaso-motor, 
and those going to glands to regulate the secretion of liquids are secretory 
fibres. Excitant fibres are those which convey excitant impulses; the 
inhibitory are those which transmit impulses by that name. (Copy 
drawing illustrating the different kinds of fibres.) 

References: 


Intercentral 











88 

Review Questions, l. In what way do nerve cells differ from all the 
other cells of the body? 2. Where are nerve cells supposed to exist singl} ■ 
3. How does a ganglion differ from a nerve center? 4. What is the function 
of the nerve cell? 5. Describe the parts of a nerve fibre and give use of 
each part. What is a nerve? (5. Why is the “gray matter supposed to be 
the true nerve substance? 7. Account for the grayish appearance of the 
nerve cells and the whitish appearance of the fibres. 8. What purpose is 
served in the body by the nervous impulse? What is the supposed nature 
of the impulse? 9. How do excitant differ from inhibitory impulses. 
10. With what will one end of a fibre always be connected? With what 
different things may the other end connect? 11. What kind of fibres are 
called afferent? What kind efferent? What intercentral? 12. Show, by a 
drawing, the general plan of connecting fibres. ISame the parts and place 
arrows to show direction of the impulses. 


II. Divisions of the Nervous System. 

There are two recognized divisions of the nervous system, known as the 
Sympathetic System and the Cerebro-Spinal System. Both these divisions 
are made up of cells and fibres and do their work through the agency of the 
nervous impulse. In both, for the most part, the cells are collected into 
ganglia, and the fibres into nerves. They differ chiefly in the arrangement 
and position of their ganglia, and in their special work in the body- 

The Sympathetic System. 

The Cells of this System are collected into small ganglia, which range in 
size from a pin-head to half an inch in diameter. They are situated in vari¬ 
ous parts of the body. The more important ones are to be found in two 
chains which are in front, and a little to each side, of the spinal column. 
(Copy drawing.) In addition to these ganglia, there are several in the heart, 
a few in the head, and many small ones scattered throughout the body. 

Many nerves come from these different ganglia, forming in some places, 
a complex network, called a plexus. Of these the cardiac plexus in the 
heart and the solar plexus of the abdomen are the most important. 

Connection of Sympathetic Fibres. Fibres from the sympathetic 
ganglia have been traced to the involuntary muscles of the alimentary 
canal, to the walls of arteries,to the spinal cord, and to the other sympathetic 
ganglia. The heart is well supplied with sympathetic fibres, part of which 
come from ganglia within it and part from ganglia situated elsewhere. 

The Function of the Sympathetic System, as inferred from the distribu¬ 
tion of its fibres, is to control the action of involuntary organs,especially those 
concerned in the maintenance of life. It cannot be stated definitely, how¬ 
ever, that this is its exclusive function, as fibres from the cerebro-spinal 
system also go to these organs. From the close connection of the two 
systems, it is difficult to separate their functions. In many instances it is 
certain tkat they together control the same organ. 





Cerebro-Spinal System. 


The ganglia of this system help to form a connected mass of nervous 
matter known as the brain and spinal cord. Going out from these, are 
nerves which make connection with all parts of the body. Thus the brain and 
cord constitute the center of the cerebro-spinal system, the parts of which 
are shown by the following table : 



1 Cerebrum 
Brain <: Cerebellum 

( Medulla oblongata 


( Spinal cord 


General Composition and Structure of Brain and Cord. The greater por¬ 
tion of these organs is made up of nerve cells and fibres. Mixed in with 
these are blood vessels, lymphatics, and enough connective tissue to hold the 
parts together. The groups of cells have a grayish color while the fibrous 
portions are whitish. Why? 

Protection of Brain and Cord. This is accomplished in three different 
ways: 1. By the bones which surround the cavities in which they lie. 
What bones are these? 2. By three membranes of connective tissue which 
envelop them. Find a description of the position and structure of these 
membranes in some physiology. 3. By a layer of liquid which completely 
surrounds them. This occupies the large spaces in the loose arachnoidal 
membrane and serves as a “watery cushion” for the brain and cord.—Why 
should the brain and cord be so carefully protected? 

The Brain is that portion of the cerebro-spinal system which lies in the 
cranial cavity. From some physiology ascertain its relative size and 
weight, its general structure, and its divisions. Is it a double or single 
organ? Name its parts. (From a model of the brain, make a “side view” 
drawing, showing the position and relative size of each part. Practice on 
this until it can be made from memory.) 

The Cerebrum forms about seven-eights of the entire brain. In what 
portion of the cranial cavity does the cerebrum lie? Locate it with reference 
to your own head. 

Note, If a pencil be placed ever the ear and pressed down, all that portion of the 
brain lying' above the pencil is cerebrum. 

Locate the “gray matter' of the cerebrum. What portion of it is “white 
matter? Of what are these “matters" composed? How is the surface for 
gray matter increased? Wdiat are the hemispheres? How are they joined? 

At the base of the cerebrum are several paired masses of nerve cells. 
The two largest of these are called the corpus striatum and the optic thalmus. 


Functions ol Cerebrum. The cerebrum is the organ of the mind and 
controls voluntary motion. These functions are performed by its cells which 
are arranged into nerve centers. The centers which are concerned in mind 
activity are called the psychic centers ; those controlling motion are called 




92 

the motor centers. The location of some of the most important of these 
centers has been discovered and mapped out, but the greater portion of the 
surface of the cerebrum is as yet “an unexplored country. ’ (Copy drawing 
showing the centers which have been located.) 

The Cerebellum. Ascertain from some physiology its size, location, 
and general structure. Give position of its gray and white matter? (Copy 
drawing to show these.) Describe its convolutions and compare with those 
of cerebrum. Numerous fibres connect the cerebellum with the cerebrum, 
medulla oblongata, and spinal cord. 

The function of the cerebellum is not understood, but it would seem, 
from experiments upon lower animals, that it assists the cerebrum in con¬ 
trolling voluntary motion. Animals from which it has been removed are 
unable to regulate and co-ordinate their voluntary motions. 

The Medulla Oblongata. Give its location, size, shape, and connections. 
Its gray and white matter have no definite arrangement, as in other parts of 
the brain, but the gray is scattered through the white in little bunches or 
clusters. 

Function. The medulla is aconductor of impulses between the brain and 
cord and contains a number of important nerve centers. The most important 
of these are the centers which control breathing aud are called the respira¬ 
tory centers. Why will an injury to these produce almost instant death? 

The Spinal Cord. Ascertain its length and diameter. Does it fill 
the entire spinal cavity? In what does it terminate at the upper end? In 
what at the lower end? Is it double or single? Give arrangement of ils 
gray and white matter. (Copy drawing to show this arrangement.) 

Functions of Cord. The spinal cord has two distinct functions: 1. It 
conducts impulses between the brain and the spinal nerves. 2. It controls 
a large number of the reflex actions of the body. Which of these functions 
is performed by the white matter of the cord? Which by the gray matter? 
Upon what do you base your conclusion? 

Cerebro-Spinal Nerves. The brain and cord are connected with the 
different parts of the body by forty-three pairs of fibre bundles, called nerves. 
Those which connect with the twain are called cranial nerves and those 
connected with the cord, spinal nerves. 

The fibres of the cerebro-spinal nerves consist of two impoitant classes. 
One class comes from the special sense-organ cells of the skin, nose, 
eyes, ears, and tongue. They convey impulses toward the brain and cord. 
What are they called? The other class makes connection with muscles and 
glands and conducts impulses away from t he brain and cord. What are they 
called? 

The Cranial Nerves are numbered in the order in which they leave the 
brain. The pair that leaves farthest toward the front is called th e first pair, 

































































94 


the next in order is the second pair, and so on for the others. The distribu¬ 
tion and function of these nerves are shown by the following table: 


Number. 


Name. 


Distribution. 


First Pair. 

Second Pair_ 

Olfactory... 

Optic. 

3rd,4th,6thPairs 

Motores oetili. 

Fiitb Pair. 

Trigeminal. 

Seventh Pair... 

Facial. 

Eighth Pair.... 

Auditorv. 

Ninth Pair. 

Glossopharyngeal 

Tenth Pair. 

Pneumogastric... 

Eleventh Pair.. 

Spinal Accessory. 

Twelfth Pair ... 

Hypoglossal. 


Mucous membrane of nose.. 

Ketina of the eye. 

Muscles of the eye. 

i Skin of face, muscles of 
jaws, mucous membrane of 
mouth, and front of tongue 

Muscles of the face. 

Internal ear. 

Hack of tongue, muscles 
of pharynx. 

Larynx,lungs,liver & stom’ch 

Muscles of neck. 

M uscles of tongue.. I 


Function. 


Nerves of smell. 

Nerves of sight. 

Control motion of eyes. 

Sensory nerve of face, controls 
muscles of mastication, 
nerve of taste to front of 
tongue. 

Control muscles of expression. 

Hearing. 

Nerve of taste to back of 
tongue, controls muscles of 
pharnjx. 

Sensory and inhibitory. 

Motion. 

Motion. 


Which of the cranial nerves are purely afferent? Which contain only 
efferent fibres? Which contain both kinds? 

The Spinal Nerves pass from the spinal cord through small openings in 
the spinal column. How many pairs of them? Each nerve joins the cord 
by two roots, the one toward the front being called the anterior root 
and the one toward the back, the posterior root. (Copy drawing.) The 
posterior root contains afferent fibres while the anterior root contains effer¬ 
ent fibres. What will be the direction of impulses in each (if the two 
roots? With what organs are the efferent fibres probably connected? With 
what the afferent? 


References: 


Review Questions. ], In what are the cerebro-spinal and sympathetic 
systems alike? How do they differ? 2. Describe the arrangement of the 
ganglia of the sympathetic system. To what organs are its nerves distribu¬ 
ted.-' What is its supposed function? 3. Where are all the ganglia of the 
cerebro-spinal system to be found? 4. How do these ganglia communicate 
with the different parts of the body? 5 Give the arrangement of gray and 
white matter in the cerebrum, cerebellum, medulla oblongata, and spinal 
cord. 6. Give the functions of the cerebrum, cerebellum, medulla oblongata, 
aud spinal cord. 7 How are the brain and cord protected? 8. Locate 
and describe the cauda equina. 9. Give the distribution and function of 
the fifth pair of nerves. 10. How do the posterior roots of the spinal nerves 
differ from the anterior roots? 





































. 


























. 








96 


III. Kinds of Nervous Action. 


The different kinds of nervous action are shown by the following table: 


r 

"Nervous Action -j 

L 


Physical 


Voluntary 

Involuntary 


Reflex 
Au tomatic 


Mental 1 . .* etc - 

( Sensation 


The Physical Activities of the nervous system pertain to the control of 
the different organs of the body. In order to control organs, the means 
must be provided both for throwing them into action and checking their 
activity. The means employed by the nervous system for doing these two 
things are the excitant and inhibitory impulses. These impulses, as said 
before, are produced in the cells of nerve centers and are transmitted to the 
different organs by nerve fibres. 

The different classes of centers which control organs are the voluntary 
centers, the reflex centers, and the automatic centers. None of these centers 
are self exciting, but they in turn, must be controlled. The means employed 
for this purpose is generally, though not always, the nervous impulse. 


Voluntary Action is controlled by the voluntary centers. Where are 
they located? These centers are made to discharge their impulses by im¬ 
pulses which they receive from the psychic, or mind centers. Hence they 
are under the control of the will. The separate steps leading up to a vol¬ 
untary action are about as follows: 1. A purely mental action, such as a 
wish or desire. 2. Stimulation of voluntary centers by a discharge of 
impulses from the psychic centers. 3. Sending out of impulses from the vol¬ 
untary centers to the muscles. 4. Contraction of muscles. 

Voluntary action is limited to the class of muscles known by that name. 


Involuntary Action refers to those activities of the body which are not 
controlled by the mind. They comprise the work of both muscles and 
glands. To what classes of nervous action do they chiefly belong? 

Keflex Action is caused by impulses from reflex action centers. The 
greater number of these centers are located in the medulla oblongata, spinal 
cord, and ganglia of the sympathetic system. They are stimulated to 
s«nd out impulses, by impulses coming to them from sense-organ cells. 
What are sense organs? Since the action is in the direction from which the 
exciting impulses come, it is called reflex , which means a bending-back. 

Experiment. Remove the head from a live frog, checking the flow of blood with a little 
cotton. Place on a board and irritate a toe by pressure or bv pricking- with a pin. Observe 
and account for the frog’s movements. Place a drop of acid on the frog’s back and observe 
the result. What is the positive evidence that the frog’s actions are not voluntary? 

The different steps in the production of a reflex action are: 1. Strong 
stimulation of sense organ cells on the outside of the body. 2. Excitation 
of reflex centers by the impulses from the sense-organ cells. 3. Sending out 























, 












M 
l I 

























1 


»J. I 


























































of impulses from the reflex centers to the muscles. 4. Contraction of mus¬ 
cles. (Copy drawing showing path of the impulses.) 

The experiment with the frog shows that voluntary muscles may also 
he made to act reflexively. This occurs when the impulses from the sense- 
organ cells are of an unusual order. Furnish illustrations. 

Problem: Trace the nervous impulses which cause a burnt finger to b« removed from 
danger before the mind knows it is hurt. 

Automatic Action is that which is caused by impulses from automatic 
centers. These when stimulated send out impulses at regular intervals, 
causing a repetition of action. The term automatic means se7/-actirig. In 
the production of this kind of action, the organs concerned are usually so 
connected that they are able to stimulate each other. They form, as it were, 
a sort of system which, when started, works independently of other portions 
of the nervous system. (See nervous control of heart, p.100.) Some of the 
automatic centers are stimulated b.y other means than the nervous impulse. 

Automatic actions maybe divided into two classes—the natural and the 
acquired. A good example of the former is t*he beating of the heart; of 
the latter, walking. In acquired action the mind exerts a controlling in¬ 
fluence, being able to throw given automatic systems into action, and to 
check entirely, or change their rate of action. To what extent is walking 
controlled by the mind? 

Mental Action in its many phases is not understood. It is known, how¬ 
ever, to be due to some form of activity of the psychic centers in the 
cerebrum. The method by which outside influences arc able to affect 
some of these centers is understood and will be studied in connection with 
the sensations. 

References: 


Questions, i. What means is employed by the nervous system in 
controlling the different parts of the body? 2. How are voluntary centers 
made to discharge their impulses? 3. Give the different steps in the pro¬ 
duction of a voluntary action. 4. Locate the reflex centers. How are 
they stimulated? 5. Give the different steps in the production of a reflex 
a«tiou. 6. Draw a diagram to shuw the course of the impulses, in the 
production of a reflex action. 7. What is the peculiarity of automatic 
centers? 8. What comprises an automatic system? 9. How may auto¬ 
matic actions be acquired? 10. Show that automatic actions are great 
labor saving contrivances. 











100 


IV. Nervous Control of Important Processes. 

Control of the Blood Supply. The most important factor in the sup¬ 
plying of blood to the different organs of the body, is the force and rapidity 
of the heart’s contractions. Let us see how these contractions are made to 
correspond with the needs of the body. In the first place, the heart has a 
small nervous system of its own, composed of sympathetic ganglia. Im¬ 
pulses from these are able to keep up its continued contractions but are 
unable either to increase or diminish the heart’s motion. 

The heart is connected with other parts of the nervous system 
by three kinds of nerve fibres: 1. A set of sensory fibres connect 
with the medulla oblongata and report the condition of the heart to the 
nerve centers locaied there. 2. A set of inhibitory fibres also con¬ 
nect with the medulla oblongata, but these carry impulses to the heart to 
slow its motion. 3. A set of excitant fibres which connect with the 
sympathetic system and bring impulses to the heart to quicken its motion. 
Impulses from the medulla oblongata and the sympathetic system 
are thus able to regulate the heart’s action. (Copy drawing from the chart 
and study it in connection with the above description.) If there should be 
a greater demand than usual for blood over the body, how will the heart be 
made to beat faster? After the extra demand has ceased, how will the 
heart be made to beat slower? 

All the heart can do by its contractions is to keep up the requisite 
amount of blood pressure in the arteries. It is unable to send a greater 
amount of blood to one organ than to another. But we know that organs 
when active receive more blood than when inactive. How is this accom¬ 
plished? If the walls of the arteries be examined they are found to contain 
bands of muscular tissue. These bands are thickest where the arteries enter 
organs and are naturally in a moderate state of contraction. Should an or¬ 
gan need more than the usual amount of blood, inhibitory impulses go to the 
muscular walls of its arteries, causing them to relax. How will this increase 
the amount of blood which enters the organ? If it is desirable to decrease 
the blood supply to a certain organ, excitant impulses cause the muscular 
walls to contract. How will this diminish the amount of blood going to 
that organ? Account for the fact that violent exercise makes the face first 
pale and then red. During hard study where is the excess of blood needed? 
How is it obtained? 

Control of Respiration. Sensory fibres extend from all parts of the 
mucous membrane, lining the air passages, to the medulla oblongata. These 
report the condition of the air passages to that part of the medulla known as 
the respiratory centers. From here one set of excitant fibres go to the dia¬ 
phragm, another to the intercostal muscles, and another set to the abdomi¬ 
nal muscles. Impulses from these produce the requisite contraction of 
muscles to cause the alternate expansion and contraction of the thorax. 
(Copy and study the drawing.) 






































































































. 









* l 







































































- 













































102 


The respiratory centers are generally stimulated by the blood which 
passes through them. If the blood contains a small amount of oxygen it 
causes the centers to send out impulses to increase the respiratory acts. If 
it contains a large amount of oxygen , the impulses are less in strength. 
This explains how physical exercise is able to increase the lorce aud 
rapidity of the respiratory acts. The muscles, at work, consume large 
quantities of oxygen aud give carbon dioxid to the blood. In this way they 
get the blood in such a condition that it can act strongly upon the respira¬ 
tory centers. 

The respiratory centers may also be stimulated in other ways. Should 
a foreign substance get into the larynx, violent coughing results. 
This is caused by nerve cells in the mucous membrane, discharging impulses 
to the respiratory centers, which stimulate them to send out impulses 
to the respiratory muscles. In like manner an irritation of the mucous 
membrane of the nostrils causes sneezing. It is thus seen that the respira¬ 
tory centers may be made to act reflexively by impulses from sense-organ cells. 

Voluntary centers in the brain are also able to stimulate the respira¬ 
tory centers and make them act under the direction «f the will. Furnish 
illustrations of this fact. 

Control of Digestive Processes. Sensory fibres leave the mucous mem¬ 
brane at all points along the alimentary canal and connect with nerve 
centers situated in the brain, spinal cord, and sympathetic ganglia. These 
make known the condition of the canal at the different centers. From these 
centers fibres go to the glands which supply the digestive fluids, to the mus¬ 
cles which are concerned in digestion, and to the icalls of the arteries which 
supply the blood to the various digestive organs. 

The food pressing against the mu cows membrane, causes a discharge of 
impulses to the different nerve centers and these, in turn, stimulate the 
organs with which they are connected. By this arrangement the food itself 
causes that work to be done which is necessary for its digestion. Show how 
the presence of food in the stomach causes the flow of the gastric juice? IIow 
will the presence of food in the pharynx induce swallowing? (Copy drawing ) 

References: 


Questions. 1 . What kind of nervous action is illustrated by the heart? 
2. What is the special work of the ganglia wil bin the heart? 3. How is 
the heart’s motion quickened? How is it slowed? 4. How is the flow of 
blood through the arteries regulated? 5. How is the flow of blood 
through the respiratory centers able to regulate the force and rapidity of 
the respiratory acts? (>. Of what advantage is it to have the respiratory 
centers controlled by strong impulses from the mucous membrane of the 
air passages? 7. Of what advantage, to have them partly under control 
of the will? 8. To what class of nervous actions do those of digestion 
belong? 9. IIow does the presence of food in the mouth nausea flow of 
the saliva? 

















































































104 


V. Sensations. 

We have already noticed the existence of a large class of nerve fibres 
which are connected with nerve cells at the outside of the body and which 
conduct impulses inward to nerve centers. What are these fibres called. - ' 
What effect do their impulses have upon reflex centers."' Ihese im¬ 
pulses when they reach the brain stimulate certain of the psychic centers, 
causing them to produce what we call a feeling or sensation. A sensation 
then is an activity of the psychic centers caused by afferent impulses. 

The purpose of all sensation is to give the mind information. Intelli¬ 
gent action makes it necessary for the mind to know the condition of the 
body itself and also the physical conditions which surround it. Sensations 
are therefore of two kinds —general and special. 

General Sensations are caused by impulses coming from many par-ts of 
the body, but which, so far as known, do not originate in nerve cells designed 
for that purpose. They seem rather to result from a general condition of 
the nervous system. As examples of general sensations may be mentioned 
hunger , thirst , nausea, pain, and the feelings of comfort and discomfort. 
Of what value are the feelings of hunger and thirst? A hat is the value of 
pain to the body? 

Special Sensations are caused by impulses which come from definite 
places at the surface of the body, called the special sense organs. There are 
at least six different kinds of special sense organs, the sensations 
which they cause being known as the special senses. These are as follows: 
sight, hearing, smell, taste, touch, and temperature. What is the general 
purpose of the special sensations? 

Every special sense apparatus has the following parts: 1. Sense-organ 
cells to originate the impulses. 2. Nerve fibres to transmit the impulses, 
d. Nerve centers which receive the impulses and give rise to the sensation. 

Each sense organ is capable of being stimulated by a single form of 
energy. This is known as the stimulus for that sense organ. For example, 
the sense organ cells of sight are made to discharge their impulses by 
the action of light. Light then is their stimulus. Furnish other illustrations. 

Touch is the simplest of the special senses. Its sense-organ cells are 
located in the touch corpuscles of the skin. Their stimulus is ordinary pres¬ 
sure. When pressure is applied to the skin the sense-organ cells produce 
their impulses which, when transmitted to the brain, cause an activity of the 
psychic centers, called the touch sensation. At what places on the body 
is the sense of touch best developed? 

Kxpekuik.iNt. Place the points of a pair <>f dividers against the skin, on tlie back of 
the hand, of <>t e who ha« be* n instructed to look in the opposite direction. Is one point 
felt or two? Repeat seve. al limes changing the distance between the points until it is fully 
determined how near together they tmist be, tube lelt as one. In like manner test other 
parts of the body, as tips of lingers and back of neck. From a comparison oi results, de¬ 
termine what portion of the body tested is most sensitive. 
















106 


The Temperature Sense. It was at one time supposed that the touch 
corpuscles were also stimulated by heat and cold, but it is now known that 
there are special sense-organ cells for temperature. When the temperature 
of objects near the skin is the same as the skin, no sensations are produced. 
But when their temperature is above or below that of the skin, the tem¬ 
perature cells are made to discharge impulses. 

Recent investigation proves the sense-organ ceils of temperature to be 
of two kinds—one kind stimulated by heat, the other by cold. 

“If a metal point, lightly weighted, be slowly and evenly moved over theskin.it stives 
rise to sensations of touch at some places and sensations of temperature at others If it be a 
little warmer than the skin, at certain places it causes a sensation of heat. If it be colder than 
the skin, it gives rise to a sensation of cold as it travels over some places. The “cold sensa¬ 
tion” spots are different from the “warm sensation’’ spots and are constant in the same in¬ 
dividual from day to day.”—Martin’s Human Body. 

The Sense of Taste. The sense-organ cells of taste are scattered over 
the upper surface of the tongue and perhaps the lower portion of the soft 
palate. They are found in little bulb-shaped organs called the taste bulbs. 
(Copy drawing.) Name and locate the different kinds of taste bulbs. r lhe 
inner ends of these cells connect with fibres which join the nerves of taste. 
The stimulus for the sense-organ cells of taste are substances iu the liquid 
state.' Solid substances, to be tasted, must first be dissolved. 

Little is known of the manner by which the different tastes are produced. 
The different kinds recognized are sweet, sour, bitter, salty, and alkaline. 
Flavors, such as vanilla and lemon, and the flavors of meats and fruits are 
really smelled, not tasted. Of what use is the sense of taste? 

The Sense of Smell. The sense-organ cells of smell are located in the 
mucous membrane of the nasal passages. These cells are stimulated to dis¬ 
charge their impulses by the passage of odors through the nostrils. The 
mucous membrane of the nose also contains ciliated cells and touch cor¬ 
puscles. The latter make it sensitive to the contact of foreign bodies. The 
olfactory, or smelling cells, are wedged in between the ciliated cells, with one 
end touchiug the surface of the membrane and the other end connected 
with fibres which transmit the impulses to the brain. 

In order to smell, the odor must be in motion through the nostrils, and 
must come in direct contact with the olfactory cells. Of what use is the 
sense of smell? Describe the nerves of smell. 

References: 

Questions, l. What is a sensation? Where and by what is it caused? 
2. How do general differ from special sensations? 3. Name three examples 
of general sensations. Name all the special sensations. 4. What is a 
special sense stimulus? Give an example. 5. What is the general pur¬ 
pose of general sensations? What of special sensations? (5. What are the 
essential parts of a special sense apparatus? ‘7. What different things must 
happen in order to produce the sensation of touch? 8. By what are the 
sense-organ cells of temperature stimulated? 9. What three kinds of 
sense-organ cells are found in the skin? Name the stimulus for each. 10. 
What kind of substances can be tasted? What kind smelled? 









































Sound and the Sense of Hearing. 

Sound is a form of vibration which is capable of affecting the organ of 
hearing. It originates in vibrating bodies. 

Experiments, l. Strike a bell an easy blow and bold against its side some light sub¬ 
stance, as a pith ball attached to a thread. Account tor the movements of the light sub¬ 
stance. 2. Sound a tuning fork by p'ucking, or striking it against the table. Its vibrations 
can be i'eit. if it is a large fork they can be seen. Place the vibrating prongs in water. Ob¬ 
serve and account for the result. 

All sound producing bodies are known to be in a state of vibration at 
the time of giving out sound. Account for the production of sound by the 
violin, organ, piano, flute, and jews-harp. All vibrations, however, are not 
sound, but only those that are more rapid than 16 per second and less rapid 
than 40,000 per second. Vibrations whose rate is less than 16, or more than 
40,000 per second, are not appreciated by the organ of hearing. 

How Sounds Differ. Sounds differ in pitch, intensity , and quality. By 
pitch is meant the height of a sound. It depends upon the rapidity of vibra¬ 
tions. By intensity is meant the energy of the vibration. It is nearly ex¬ 
pressed by the word loudness. It depends upon the amplitude , or width, of 
the vibrations. Quality is that peculiarity of sound which enables us to 
distinguish one sound from another having the same pitch and intensity. 

Expeuiments. l, l>raw the edge of a visiting card over the teeth of a comb. The 
sound produced from each separate tooth may be considered a vibration. Account for the 
fact that a slow motion produces a tone of low pitch and a rapid one, a tone of high pitch. 2. 
With a violin or guitar show how pitch is affected by ihe length, tension, and size of the 
strings, ii. Show by plucking a strinir of a guitar, first lightly and then lorcibly, that the 
loudness of the sound depends upon the amplitude of its vibrations. 

Sound Vibrations may be transmitted, or carried, from where they orig- 
nate to other places by all elastic substances. The atmosphere, however, since 
it presses in close against vibrating bodies and is in sufficient abundance to 
form a connecting medium between all things on the earth, is the most im¬ 
portant transmitter of sound. Vibrating bodies set the air in contact with 
them into vibration. These vibrations pass through the air in the form of 
waves, called sound leaves. When sound waves strike against delicately 
poised substances they set them into vibration. 

Experiment. Wave a fiat stiff body, such as a chart or board, back and forth through 
tiie air, in front of, and about ten feet away from, a large sheet of paper which is held loosely 
by its upper corners. The moving object imparts its motion to the air and the air transmits it 
to the paper, causing it to vibrate. Apply the principles involved in this experiment to the 
origin, transmission, and effect of sound waves. 

Sound Waves are not made up of crests and troughs, like the waves on 
water, but are composed of condensed and rarefied portions. The condensed 
portion is formed when the vibrating body moves toward the air and the 
rarefied portion when it recedes from it. The length of a sound wave is the 
distance across one condensed portion and one rarefied portion. Sound 
waves vary in length from a few inches to several feet. 































































I 
























110 


Sound waves sustain a very important relation to the subject of physi¬ 
ology. By means of them, man, in common with most animals, becomes ac¬ 
quainted with a certain condition of surrounding objects and is able to com¬ 
municate with his fellows. The body, therefore, is supplied with a contri¬ 
vance for producing sound vibrations and also a contrivance, by means of 
which,they are able to stimulate a part of the brain and produce the sensa¬ 
tion of hearing. Name and locate these contrivances. 

The Organ of the Voice. In the middle part of the larynx the air pas¬ 
sage is much narrowed by two pairs of folds in the mucous membrane. 
These are the vocal cords , the lower pair being called the true cords and 
the upper pair the false cords. In the lower cords are ligaments and muscles 
which connect with the cartilagenous walls of the larynx. (See description 
of larynx in some physiology.) The pieces of cartilage, by changing the 
shape of the larynx, are able either to stretch or loosen the cords. When it 
is desirable to produce a sound the cords are drawn across the opening and 
the air from the lungs forced over them. The effect of this is to cause them 
to produce sound vibrations. The vibrations of the cords are reinforced and 
modified by the cavities connected with the larynx. 

The Organ of Hearing consists of a contrivance for euabling a sound 
wave to stimulate the sense-organ cells of hearing and cause them to send 
impulses to the brain. This organ consists of three parts: The external 
ear, the middle ear, and the internal ear. The auditory, or hearing cells,are 
located in the internal ear. 

The External Ear consists of the part on the outside of the head, called 
the pinna, or auricle, and the tube leading into the internal ear, called the 
auditory canal. This canal is closed, at its inner end, by the membrane of 
the middle ear, called the membrana tympani. 

The pinna, by its peculiar shape, is able to reflect sound waves into the 
auditory canal which, in its turn, conducts them to the 

Membrana Tympani. This membrane consists of three thin layers. The 
outer layer is a continuation of the membrane lining the auditory canal; the 
inner, is a part of the membrane of the internal ear; while the middle, is a 
layer of connective tissue. Being thin and delicately poised, the membrana 
tympani is easily made to vibrate by the sound waves passing into the audi¬ 
tory canal. 

The Middle Ear, or Tympanum, is an irregular cavity in the temporal 
bone. It is lined with mucous membrane and is connected with the pharynx 
by a canal, known as the eustachian tube. Extending across it and connect¬ 
ing the membrana tympani with a membrane closing a passage to the in¬ 
ternal ear, called the fenestra ovalis, is a chain of three small bones. (Find 
names for these bones.) The eustachian tube admits air into the mid¬ 
dle ear and, in this way, maintains an equality of atmospheric pressure on 
the two sides of the membrana tympani. 









n-2 

Experiment. Close the nose and mouth tightly with the hand and attempt to exhale 
air from the lungs. Account for the pressure in the ears. Repeat the experiment, attempting 
to inhale instead of exhale. 

The purpose of the chain of bones is to transmit/ vibrations. By means 
of it the vibrations are carried from the membrana tympani to the 

internal Ear, or Labyrinth. This division of the ear consists of a groupof 
membranous tubes which lie in a corresponding groupof bony channels in the 
temporal bone. There are three parts to the labyrinth: The semi-circular 
canals, the cochlea , and the vestibule. The different parts are connected, 
and the cochlea and semi-circular canals may be considered as branches of 
the vestibule. (Copy drawing from chart, naming the parts.) 

Of the different parts of the labyrinth, the cochlea is perhaps the most 
important, as it contains the auditory cells. It is a spiral tube, coiled like a 
snail shell, with three internal divisions running its entire length. (Copy 
thedrawing.) One division connects with the vestibule and is called the 
scala vestibuli. Another reaches to the tympanum and is called the scala 
tympani. The other lies between these two and is called tne scala media , or 
ochlear canal. This is the true organ of hearing and contains the 

Auditory Cells. These are spread out over a thin membrane, called the 
basilar membrane. Fibres from the auditory nerve connect with the cells 
and transmit their impulses to the brain . Sound vibrations are communi¬ 
cated to them by the liquid which occupies the entire internal ear. 

How we Hear. The sound vibrations which originate in some vibrating 
body are transmitted by the air to the external ear. The pinna and auditory 
canal direct the vibration against membrana tympani and this is made 
to vibrate. The vibration of this membrane causes the chain of bones to 
vibrate and it, in turn, communicates the vibration to the liquid in the 
labyrinth. This liquid vibrating against the two sides of the scala media, 
sets the auditory cells into vibration, causing them to discharge nervous 
impulses. These impulses, on reaching the brain, cause the sensation of 
hearing. 

Pro ii lem : Trace a sound vibration from a bell to the auditory cells and the impulse it 
causes, from there to the brain. 

Marty things connected with hearing are not yet understood. The 
smallness of the true organ of hearing and its position in the temporal bone 
make its study exceedingly difficult. 

The Function of the Semi-circular Canals has not, as vet, been fully 
demonstrated. On account of the directions which they extend through 
the temporal bone and the effect which their removal has upon lower 
animals, they are supposed to assist in keeping the body balanced. 

Care of the Ear. The ear being a delicate organ, injury to it often 
results from careless or rough treatment. The ear wax should not be “picked” 
out of the auditory canal. The ear has a way of its own for discharging it, 
besides the practice is attended with considerable danger. Children's ears 











- 


- 

■ 


















114 


should never be pulled or boxed. In removing foreign substances which may 
have accidently gotten into the ear, use only gentle means- In case of 
serious trouble there should be no delay in consulting a physician. 
References: 


Review Questions. 1. What is sound? In what kind of bodies does 
it originate? By what is it carried, or transmitted? What effect may it 
have upon delicately poised bodies? 2. Define pitch, intensity, and quality 
of Sound. Upon what does pitch depend? Upon what quality? 8. How 
is a vibrating body able to set the air into vibration? 4. Describe a sound 
wave. What uses are made of sound waves by most animals? 5. Why is 
the body supplied with a sound producer and a sound receiver? 6. De¬ 
scribe the method of producing the voice. 7- Make a sectional drawing of 
the ear, naming the parts. 8. Where are the sense-organ cells of hearing 
located? How are they stimulated? 9. Give function of the pinna, audi¬ 
tory canal, membrana tympani, eustachian tube, chain of bones, liquid in 
the internal ear, auditory cells, auditory nerve, and the auditory psychic 
centers. 10. How do we hear? 11. Why should the ears not be “picked?’ 


o 


Light and the Sensation of Sight. 


Light is supposed to be a form of wave-like motion, or vibration, thrown 
off from bodies heated to a very high temperature. Such bodies are said 
to be luminous. Name examples. Light waves pass from luminous 
bodies, in straight lines, in all directions. When they strike other bodies 
they maybe reflected , absorbed, or allowed to pass through. Name a body 
which reflects light; one which permits it to pass through itself. A single 
line of light is called a light ray. A collection of rays is called a beam of 
light. 

When light passes from one medium into another of different density, as 
for instance from air into water, it is bent out of its course. This bending is 
called refraction. If different light rays are bent so that they meet at a point., 
they are said to be focused, and the point of meeting is called the focus. If 
rays which are reflected from a given point on a body are focused, they form 
a picture or image of that point. A collection of the images of all the re¬ 
flected points of a body forms an image of the whole body. 

Experiments. 1. Heat an iron or platinum wire in a clear gas flame. Observe that as 
t is heated to a high temperature it gives out light rays, or becomes luminous. 2. With a 
migror, a piece of window pane, and a piece of black cloth, illustrate the reflection, transmis¬ 
sion, and absorption of light rays. 3. The refraction of light may be illustrated by standing 
a book, or block of wood, by the side of an empty pan, in the sunlight, so that the end of the 
shadow falls on the bottom of the pan. Mark the place where the shadow terminates and All 
the pan with water. Account for the shadow’s changing in length. 4. Place acci»in the 
center of an empty pan and have the members of the class stand where the coin is barely out 



















* * S 






1 . 























116 

ef sight over tlie edge of the pan. Fill the pan with water and account for the coin s coming 
into view. 5. Hold a piece of card-board, about 8 inches square and having a smooth, round 
bole in it an eighth of an inch in diameter, in front of a lighted candle in a darkened room. 
Hack of the opening place a muslin, or paper,screen. An image of the candle will be formed on 
the screen. Account for the fact that it is inverted. Make a drawing to represent its for¬ 
mation. 6. Hold a convex spectacle lens between the card-board and screen so that the rays 
of light pass through it. The image should become smaller and more distinct. 

A complete knowledge of light can only be obtained by a study of 
Physics. A slight knowledge of it is necessary here, because light rays 
stimulate the sense-organ cells of sight and thereby enable us to see objects. 
In order to see an object four things must happen: 1. Light rays must pass 
from the object to the eye. 2. These rays must stimulate the sense-organ 
cells to discharge their impulses. B. These impulses must be transmitted 
to nerve centers in the brain. 4. These centers, in response to the impulses, 
must become active. This activity is the sensation of sight. 

The Organ of Sight consists of the eyeball, or globe of the eye, to¬ 
gether with the tissues for its protection and control. 

The Globe of the Eye is a contrivance for focusing the rays of light 
from an object, upon the sense-organ cells of sight. Its parts are as follows : 

The cornea , a clear, transparent membrane,is in the center of the front 
of the eye. It fits into the sclerotic coat which surrounds it on all sides, as 
the crystal of a watch into its case. It admits light into the globe. The 
sclerotic coat is white, dense, and firm. It surrounds the remaining portion 
of the eyeball, except where the optic nerve enters. At this place it con¬ 
tinues back as the sheath of the nerve. The portion of it seen in front, is 
called the “white of the eye ” 

The sclerotic coat is lined by a dark colored coat, the choroid , which is 
crowded with the blood vessels that furnish most of the nourishment to the 
eye. On account of its color it is able to absorb surplus rays of light. The 
choroid coat is continued forward into the circular curtain back of the cornea 
called the iris. The iris is the colored portion of the eye. In the center of 
the iris is a circular opening called the pupil. This opening is to admit 
light into the inner portion of the eyeball and its size is regulated by the 
iris. The iris contains two sets of involuntary muscles—one set, of circular 
muscles, surrounds the pupil, and the other, of radiating muscles, are at¬ 
tached between the inner and outer margins of the iris. W hat effect will a 
contraction of the circular muscles have on the size of the pupil? What, 
the contraction of the radiating muscles? By increasing and diminishing 
the size of the pupil, the iris is able to regulate the amount of light which 
enters the inner eye. 

Lying next to the choroid coat, in the back portion of the eyeball and 
covering about two-thirds of its inner surface, is the retina. Though only 
about one-fiftieth of an inch in thickness, it is very complex in structure 
and contains the sense-organ cells of sight. These cells, on account of their 
peculiar shapes, are called the rods and cones. Fibres from the optic nerve 




118 


c®nnect with these cells and conduct their impulses to the brain, that 
portion of the retina immediately back of the pupil, called the yellow spot, 
is the place where it is most sensitive. At the place where the 
optic nerve enters the eye, the rods and cones are absent. This is called the 
blind spot. 

Experiment. Close the left eye and with the right, gaze steadily at the spot on the 
eft side of the page. Starting with the hooka toot or more from the face, move it slowly 



toward the eye. One place will be found where the spot on the right entirely disappears. On 
bringing it nearer, however, it is again seen. As the bonk moves forward or backward, the po¬ 
sition of the image of this spot on the retina changes. Wl»ere is it when the spot cannot be seen? 

The crystalline lens is situated immediately back of the iris. It is a 
transparent solid body, convex on both sides, being about one-third of an 
inch in diameter and one-fourth of an inch thick. It is quite elastic. It is 
si rrounded and held in position by a membranous capsule, the edges of 
w lich, connect with an extension of the supporting connective tissue of 
the retina. 

Surrounding the lens, and lying at the junction of the iris and ehoroid 
coat,is a circular band of involuntary muscle, called bhe ciliary muscle. Its 
contraction has the effect of diminishing the diameter and increasing the 
thickness of the lens. 

The eye contains two liquids. A watery liquid which lies between the 
lens and the cornea, is called the agueous humor. It serves to hold the 
cornea in shape. Lying between the lens and retina is a elear jelly-like 
liquid,called th evitreous humor. This serves to hold the walls of the eyeball 
in shape. (Copy from the chart the drawing of the globe of the eye and 
name its parts. Practice on this drawing until it can be made from memory.) 

Experiment. In the center of one end of a chalk box, having a light fitting lid, cut a 
round hole half an inch in diameter. Over this hole fasten a small pi' ce of tin which has in 
its center a smooth, round hole tfhree-sixteenths of an inch in diameter, back of the hole 
asten by a suitable support a convex lens, such as may be obt. lined from an old pair of specta¬ 
cles At the upper left hand corner of the.same end of the box, cut another opening, making 
it •ne-l'oiirth of an inch in diameter. Fit a stiff piece of white paper in iheluck end of the 
bok and arrange it so that its position may be shifted. 

If the lid be placed on the box and the opening in tlie center turned toward a window, 
am inverted image will be seen on the paper screen by looking in the hole at the corner of the 
box. Care must be taken tlia tflie head does not obsl met the rays of light which pass from 
the window to the hole. The distinctness of the image wilt be increased by a coat of black 
ptoint on the inside of the box. Compare the box to the eyeball, part for part. 

Focusing Power of the Eye. The instruments used in Physics for 
focusing light rays are called lenses. The eye is provided with two of these. 
The cornea with the liquid behind it, forms one of them an<l the crystalline 
lens is the other. Light rays from the surfaces of birdies are, by means of 
these brought to a focus upon the retina. 








130 


Iu focusing objects, at different distances, it is necessary for the crystal¬ 
line lens to change its shape. In focusing the rays from near objects, it 
becomes thicker and more con vex than when focusing the rays from distant 
objects. These changes are brought about by the capsule and ciliary muscle 
working in opposition to the elasticity of the lens. When the lens is to be made 
more convex, the ciliary muscle contracts and presses the lens out of its nat¬ 
ural shape; when less convex, the ciliary muscle relaxes and the elastic force of 
the lens makes it thinner. The changing of the shape of the lens to suit 
the distance of the object is called accommodation. 

Experiment. Hold a pencil between the eyes and window, looking at the window. 
Why does the pencil appear blurred and indistinct? Keeping the pencil in the same position 
look af it instead of the window. Account, for the appearanc i of the window. Look from one 
to the other several times in succession. Is it easier to change the gaze lrom the distant to 
the near object, or vice versa? Why? 

How We See. Kays of light from objects enter the eye and are focused 
by the cornea and crystalline lens upon the retina. Here they stimulate the 
rods and ciwies causing them to send the impulses to the brain which cause 
t he sensation of sight. Review the parts of the eye and determine how each 
part helps in the matter of seeing? 

Defects in Focusing Power. An eye in a natural, or normal, condition 
is able, when at rest, to focus objects which are 20 feet or more away and is 
able to accommodate itself to objects as near as live inches. An eye is said 
•to he myopic or shortsighted when it is unable to focus light rays from dis¬ 
tant objects. In such an eye, the ball is too long and the image falls in 
front of the retina. A longsighted or hypermetropic eye isone which can focus 
the rays from distant objects but not those from near objects. In such an eye 
the ball is so short that the image of the object, if formed, would fall behind 
the retina. These defects in focusing are remedied Dy wearing glasses 
whose lenses are shaped so as to correct the defect in the eye. Short¬ 
sightedness is corrected by a concave lens and longsightedness by a convex 
lens. Why? 

In astigmatism all parts ot the eye fail to focus at the same distance. 
Asa result one part of an object is seen distinctly while another part is dim. 
This defect is due to some fault in the crystalline lens. It is remedied by 
lenses ground to correct the particular defects which happen to he present 
gri a given eye. 

The Movements of the Eyeball are brought about by the action of six 
small muscles attached to its outside. Four of these, the recti muscles, are 
attached between the upper, lower, inner, and outer sides of the ball,and the 
back portion of the socket. These are aide to turn the eye upward, down¬ 
ward, inward, and outward. The other two, the oblique muscles, are at¬ 
tached between the upper and lower portions of the ball and the sides of the 
socket. These rotate the eye. (Copy and understand the drawing.) 




122 


How Ml©Eyeball ia Protected, l. By the bony cavity in which it is 
placed. 2. By cushions of fat which line the cavity. 3. By the lids. 
How? 4. By a thin sensitive membrane, the conjunctiva , which covers 
the front of the ball and the under surface of the lids. This membrane 
prevents foreign bodies from getting behind the ball. 5. By the tears. How? 
(Study the plan by which the tears are supplied to and removed from the 
eyes. Copy drawing.) 6. By the eyebrows aud eyelashes. How? 

Care of tiie Eyes. On account of their delicacy the eyes are easily in¬ 
jured by careless use. If the following precautions are observed many of 
the common ailments of the eyes may be prevented: 1. Never read where 
the light is very intense or very dim. 2. When the eyes hurt quit using 
them. 3. Never hold a book so that the smooth page reflects light into the 
eyes. The bos‘ way is to sit or stand so that light passes from over the 
shoulder to t.c book. 4. Never study by a lamp which is not shaded. 
5. Whemtha eyes are weak, wash them frequently in water containing 
enough salt to slightly smart them. When something serious affects the 
eyes, consult a physician. 

References: 


Review Questions, l. What is the supposed nature of light? In what 
kind of bodies does it originate? 2. When is light reflected? When ab¬ 
sorbed? When refracted? When transmitted? 3. How is an image formed? 

4. What different things must happen in order that we may see an object? 

5. Make a sectional drawing of the eyeball and name its parts, 6. Give 
the function of the cornea, pupil, iris, retina, choroid coat, sclerotic coat, 
crystalline lens, ciliary muscle, optic nerve, aqueous humor, virtreous 
humor, and conjunctiva. 7. Trace a ray of light from a visible object, 
through the different media, to the retina and the impulse it causes from 
there to the brain. 8. What portions of the eyeball are transparent? Why 
should they be? 9. What is accommodation? How is it accomplished? 
10. What is the focusing power of a natural eye? When is an eye myopic? 
When hypermetropic? 11. What is astigmatism? How is it remedied? 12. 
Show how the different movements of the eyes are brought about. In what 
different ways is the eyeball protected? 14. Describe the conjunctiva and 
give its function. 15. Give directions for the proper care of the eyes. 


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Hygiene of Nervous System. 

Like other portions of the body the nervous system, particularly the 
brain, may be injured by overwork, or by careless treatment, and impioved by 
proper care and use. Mental work is conducive to the health of the nervous 
system. Even severe mental exertion may be undergone without bad effects, 
provided proper hygienic conditions are observed. 

Plenty of Sleep js one of the first requirements of the nervous system. 
This is the time during which the exhausted brain tissues are being replen¬ 
ished. To shorten the natural period of sleep is to weaken the brain and 
lessen its working force. No one should attempt to get along with less than 
eight hours of sleep each day and most people require more. 

Physical Exercise is another requirement of healthy nervous action. 
(See topic on physical exercise, p. 78.) Mental work causes an excess of 
blood to be sent to the brain and a diminished amount to other parts of 
the body. Sufficient physical exercise should, at least, be taken to redistrib¬ 
ute the blood and equalize the circulation. Light exercise, therefore, 
should follow hard study. The student on retiring at night is greatly 
assisted in getting to sleep, and put in better condition for the next day’s 
work, by 15 or 20 minutes of light gymnastics. 

Fretting and Worrying are unhealthful forms of nervous activity which 
should be carefully avoided. Certainly the vast quantity of nervous energy 
which may be expended in these ways catnut be used in doing mental work. 
A fretting person may be likened to the leaking boiler of a steam engine. 
The escaping steam nut only lessens the working power of the engine but 
is disagreeable and distracting as well. “It is worry not work that causes 
the mental wreck.” 

Mental States have much to do with the healthfulness of the nervous 
system. Angry and resentful feelings and manifestations of e»vy and 
jealousy are known to work positive injury to the nervous system as well as 
the disposition, while brooding over real or imaginary wrongs has caused 
many cases of insanity. On the other hand, cheerfulness, contentment, 
patience, and manifestations of good will and good fellowship are necessary 
conditions for healthful nervous action. 

What We Eat and Drink also has an important effect upon the nervous 
system. Like other portions of the body, it fares best when there is a 
liberal supply o? wholesome, well-cooked food. There is a class substances, 
deserving special consideration, which have an important effect upon the 
nervous system without themselves undergoing any change in the body. 
These substances are of two general kinds, known as 



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126 

Stimulants and Narcotics. 

Stimulants act upon the nervous system to increase its activity while 
the general effect ot' narcotics is to lessen its activity. Although the use of 
these drugs in disease may be beneficial and often invaluable, the frequent 
use of them in health is decidedly injurious. Among some of the more 
common ones may be named alcohol, morphia, the nicotine ot tobacco, the 
caffeine of coffee, and the theine of tea. 

Alcohol is the intoxicating principle in the usual saloon drinks such as 
whisky, beer, ale, wine, etc. It is formed by the fermentation of fruits 
and grains. When pure it is a colorless liquid, lighter than water, with an 
agreeable odor and a hot, pungent taste. It is inflammable, and burns with 
a clear, hot flame. It is able to dissolve many substances in water, such as 
oils, gums, and resins. It has a strong affinity for water and is able to ab- 
! sorb it from organic substances. Its first effect upon the nervous system is 
that of a stimulant, though in large doses it acts as a narcotic. 

Experiments. 1. Place a tablespoon ful of alcohol in a saucer and ignite it with a 
burning match. Observe that tile flatne contains no soot and gives little light hut great heat. 
2. Pour some alcohol over the white of a raw egg and observe the effect. The coagulation of 
the albumen is due to the absorption of water from it by the alcohol. 3. Place a drop of 
blood on a glass slide and place over it a cover glass. Examine under a compound microscope. 
Then add a tiny drop of alcohol to the blood on the slide and examine a second time. The 
shruken condition of the corpuscles is caused by the alcohol coagulating the albumen in them. 

Alcohol has some very important uses. It is used as a combustible for 
obtaining a hot, smokeless flame. It is used in dissolving gums, oils, and 
resins for medicai purposes and for use in the arts. It is used by scientists 
in preventing the decay of animal and veget ible substances and, by some 
physicians, in the treatment of diseases where a stimulant is needed. 

The Evil Effects of Alcohol n e in its use as a beverage. It has been 
proven to be a poison, whether used in large or small quantities, and is in no 
sense to be regarded as a food. Introduced into the body, it weakens the 
nervous system by making it too active; it hardens the tissues by absorbing 
water from them; it interferes with digestion and the natural circulation of 
the blood ; it so disturbs the action of the brain as to induce temporary in¬ 
sanity , or drunkenness, which, if frequently repeated, leads to permanent 
insanity; it rapidly weakens the stomach, liver, and kidneys, rendering 
them unfit for their important work. But, worst of all, it creates an appe¬ 
tite for itself that causes the victim to take it in larger and larger doses until 
death or insanity is the result. As a beverage, alcohol, in all its forms, 
should be carefully avoided, anfl its use even as a medicine is gravely ques¬ 
tioned. 

Alcoholic drinks are often used for the purpose of keeping the body 
warm. By stimulating the circulation and increasing the flow of blood 
through the skin it will make one feel warm. But for the reason that it 

























































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128 


undergoes no chomical change in the body it furnishes no heat. In the 
end bodily hea't is diminished by taking alcohol and, as soon as its stimu¬ 
lating effects are over, one will suffer intensely if exposed to severe cold. 

Morphia i s perhaps the most powerful and dangerous of the narcotics. 
It is an extract from opium and is a valuable medicine. Its use, however, is 
attended with great danger, as the opium habit is easily contracted and is 
even worse in its effects than the alcohol habit. 

Nicotine is an oily, colorless liquid obtained from tobacco. It is emi¬ 
nently a poison. Taken in very small quantities it is a mild stimulant and 
if the doses are repeated a habit is formed which is very hard to break. To¬ 
bacco is used for the peculiar stimulating effects of this drug. The tobacco 
habit, while not so serious in its results as the as the alcohol and morphine 
habits, is of no benefit, is a great and useless expense, and, in many instances, 
causes a derangement of the healthy actions of the body. Its use by the 
young is especially injurious, as it decidedly interferes with the proper de¬ 
velopment of both body and mind- To the bad effects of the nicotine may 
also be added those of questionable substances used either for their agree¬ 
able flavor or as adulterations. Perhaps the worst thing yet produced in the 
tobacco line is the cigarette. Its use has been the direct cause of many 
deaths within the last few years. 

The Caffeine of coffee and Theine of tea are mild stimulants, and it is for 
the effects of these drugs that tea and coffee are so extensively used. Tea 
and coffee are similar in their action, though they affect persons differently. 
Where the system needs a stimulant they are preferable to alcohol. Their 
habitual use, however, interferes with the healthy action of the body and 
for that reason should be avoided. Brain workers especially experience bad 
effects from their use. The continued practice of some students of drinking 
coffee and tea in order to study late at night can only end in the loss of 
health. 

References: 


Questions. ]. Of what value is sleep to the nervous system? 2. What 
is the special value of physical exercise to the brain worker? 3. How do 
fretting and worrying lessen one’s power to work? 4. What mental states 
are conducive to the healthfillness of the nervous system? What ones in¬ 
terfere with its healthy action? 5. IIow do stimulants differ from narco¬ 
tics? How do both differ from foods? 6. Give the properties and uses of 
alcohol. 7. What are a few of the bad effects which it has upon the body? 
8. IIow is alcohol able to make one feel warm? 9. What bad effects has 
nicotine upon the body? 10. Is the general effect of tea and coffee beneficial 
or harmful? 11. Why do brain workers experience worse effects from the 
use of stimulants and narcotics than others? 

































